diff --git a/src/bun.js/WebKit b/src/bun.js/WebKit
index c0c648e5a793ac..c3712c13dcdc09 160000
--- a/src/bun.js/WebKit
+++ b/src/bun.js/WebKit
@@ -1 +1 @@
-Subproject commit c0c648e5a793acb9a6ee48c898e98a9afc8bd9cd
+Subproject commit c3712c13dcdc091cfe4c7cb8f2c1fd16472e6f92
diff --git a/src/bun.js/bindings/JSEnvironmentVariableMap.cpp b/src/bun.js/bindings/JSEnvironmentVariableMap.cpp
index d0514ae781935e..3d59d9c45947df 100644
--- a/src/bun.js/bindings/JSEnvironmentVariableMap.cpp
+++ b/src/bun.js/bindings/JSEnvironmentVariableMap.cpp
@@ -166,11 +166,10 @@ JSValue createEnvironmentVariablesMap(Zig::GlobalObject* globalObject)
             if (auto index = parseIndex(identifier)) {
                 ZigString valueString = { nullptr, 0 };
                 ZigString nameStr = toZigString(name);
-                JSValue value = jsUndefined();
                 if (Bun__getEnvValue(globalObject, &nameStr, &valueString)) {
-                    value = jsString(vm, Zig::toStringCopy(valueString));
+                    JSValue value = jsString(vm, Zig::toStringCopy(valueString));
+                    object->putDirectIndex(globalObject, *index, value, 0, PutDirectIndexLikePutDirect);
                 }
-                object->putDirectIndex(globalObject, *index, value, 0, PutDirectIndexLikePutDirect);
                 continue;
             }
         }
diff --git a/src/bun.zig b/src/bun.zig
index 605855ddbaea85..dfa870098e1ca8 100644
--- a/src/bun.zig
+++ b/src/bun.zig
@@ -2005,12 +2005,12 @@ pub const win32 = struct {
     ) !void {
         const flags: std.os.windows.DWORD = w.CREATE_UNICODE_ENVIRONMENT;
 
-        const image_path = &w.peb().ProcessParameters.ImagePathName;
+        const image_path = windows.exePathW();
         var wbuf: WPathBuffer = undefined;
-        @memcpy(wbuf[0..image_path.Length], image_path.Buffer);
-        wbuf[image_path.Length] = 0;
+        @memcpy(wbuf[0..image_path.len], image_path);
+        wbuf[image_path.len] = 0;
 
-        const image_pathZ = wbuf[0..image_path.Length :0];
+        const image_pathZ = wbuf[0..image_path.len :0];
 
         const kernelenv = w.kernel32.GetEnvironmentStringsW();
         defer {
@@ -2062,7 +2062,7 @@ pub const win32 = struct {
             .hStdError = std.io.getStdErr().handle,
         };
         const rc = w.kernel32.CreateProcessW(
-            image_pathZ,
+            image_pathZ.ptr,
             w.kernel32.GetCommandLineW(),
             null,
             null,
diff --git a/src/cli/create_command.zig b/src/cli/create_command.zig
index 6e6a5cabcc8c4b..bd209664ed9eb9 100644
--- a/src/cli/create_command.zig
+++ b/src/cli/create_command.zig
@@ -2307,7 +2307,7 @@ const GitHandler = struct {
                 process.stderr_behavior = .Inherit;
 
                 _ = try process.spawnAndWait();
-                _ = process.kill() catch undefined;
+                _ = process.kill() catch {};
             }
 
             Output.prettyError("\n", .{});
diff --git a/src/cli/install.ps1 b/src/cli/install.ps1
index 22a907a4f7fed8..285a1b073bcfe9 100644
--- a/src/cli/install.ps1
+++ b/src/cli/install.ps1
@@ -1,35 +1,96 @@
 #!/usr/bin/env pwsh
 param(
   # TODO: change this to 'latest' when Bun for Windows is stable.
-  [string]$Version = "canary"
+  [String]$Version = "canary",
+  # Forces installing the baseline build regardless of what CPU you are actually using.
+  [Switch]$ForceBaseline = $false,
+  # Skips adding the bun.exe directory to the user's %PATH%
+  [Switch]$NoPathUpdate = $false,
+  # Skips adding the bun to the list of installed programs
+  [Switch]$NoRegisterInstallation = $false
 );
 
+# filter out 32 bit + ARM
+if ($env:PROCESSOR_ARCHITECTURE -ne "AMD64") {
+  Write-Output "Install Failed:"
+  Write-Output "Bun for Windows is only available for x86 64-bit Windows.`n"
+  exit 1
+}
+
+# This corresponds to .win10_rs5 in build.zig
+$MinBuild = 17763;
+$MinBuildName = "Windows 10 1809"
+
+$WinVer = [System.Environment]::OSVersion.Version
+if ($WinVer.Major -lt 10 -or ($WinVer.Major -eq 10 -and $WinVer.Build -lt $MinBuild)) {
+  Write-Warning "Bun requires at ${MinBuildName} or newer.`n`nThe install will still continue but it may not work.`n"
+  exit 1
+}
+
 $ErrorActionPreference = "Stop"
 
-# This is a functions so that in the unlikely case the baseline check fails but is is needed, we can do a recursive call.
+# These three environment functions are roughly copied from https://github.com/prefix-dev/pixi/pull/692
+# They are used instead of `SetEnvironmentVariable` because of unwanted variable expansions.
+function Publish-Env {
+  if (-not ("Win32.NativeMethods" -as [Type])) {
+    Add-Type -Namespace Win32 -Name NativeMethods -MemberDefinition @"
+[DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
+public static extern IntPtr SendMessageTimeout(
+    IntPtr hWnd, uint Msg, UIntPtr wParam, string lParam,
+    uint fuFlags, uint uTimeout, out UIntPtr lpdwResult);
+"@
+  }
+  $HWND_BROADCAST = [IntPtr] 0xffff
+  $WM_SETTINGCHANGE = 0x1a
+  $result = [UIntPtr]::Zero
+  [Win32.NativeMethods]::SendMessageTimeout($HWND_BROADCAST,
+    $WM_SETTINGCHANGE,
+    [UIntPtr]::Zero,
+    "Environment",
+    2,
+    5000,
+    [ref] $result
+  ) | Out-Null
+}
+
+function Write-Env {
+  param([String]$Key, [String]$Value)
+
+  $RegisterKey = Get-Item -Path 'HKCU:'
+
+  $EnvRegisterKey = $RegisterKey.OpenSubKey('Environment', $true)
+  if ($null -eq $Value) {
+    $EnvRegisterKey.DeleteValue($Key)
+  } else {
+    $RegistryValueKind = if ($Value.Contains('%')) {
+      [Microsoft.Win32.RegistryValueKind]::ExpandString
+    } elseif ($EnvRegisterKey.GetValue($Key)) {
+      $EnvRegisterKey.GetValueKind($Key)
+    } else {
+      [Microsoft.Win32.RegistryValueKind]::String
+    }
+    $EnvRegisterKey.SetValue($Key, $Value, $RegistryValueKind)
+  }
+
+  Publish-Env
+}
+
+function Get-Env {
+  param([String] $Key)
+
+  $RegisterKey = Get-Item -Path 'HKCU:'
+  $EnvRegisterKey = $RegisterKey.OpenSubKey('Environment')
+  $EnvRegisterKey.GetValue($Key, $null, [Microsoft.Win32.RegistryValueOptions]::DoNotExpandEnvironmentNames)
+}
+
+# The installation of bun is it's own function so that in the unlikely case the $IsBaseline check fails, we can do a recursive call.
 # There are also lots of sanity checks out of fear of anti-virus software or other weird Windows things happening.
 function Install-Bun {
   param(
-    [string]$Version
+    [string]$Version,
     [bool]$ForceBaseline = $False
   );
 
-  # filter out 32 bit and arm
-  if ($env:PROCESSOR_ARCHITECTURE -ne "AMD64") {
-    Write-Output "Install Failed:"
-    Write-Output "Bun for Windows is only available for x86 64-bit Windows.`n"
-    exit 1
-  }
-
-  # .win10_rs5
-  $MinBuild = 17763;
-  $MinBuildName = "Windows 10 1809"
-  $WinVer = [System.Environment]::OSVersion.Version
-  if ($WinVer.Major -lt 10 -or ($WinVer.Major -eq 10 -and $WinVer.Build -lt $MinBuild)) {
-    Write-Warning "Bun requires at $($MinBuildName) or newer.`n`nThe install will still continue but it may not work.`n"
-    exit 1
-  }
-
   # if a semver is given, we need to adjust it to this format: bun-v0.0.0
   if ($Version -match "^\d+\.\d+\.\d+$") {
     $Version = "bun-v$Version"
@@ -44,16 +105,35 @@ function Install-Bun {
 
   $Arch = "x64"
   $IsBaseline = $ForceBaseline
-
-  $EnabledXStateFeatures = ( `
-    Add-Type -MemberDefinition '[DllImport("kernel32.dll")]public static extern long GetEnabledXStateFeatures();' `
-      -Name 'Kernel32' -Namespace 'Win32' -PassThru `
-  )::GetEnabledXStateFeatures();
-  $IsBaseline = ($EnabledXStateFeatures -band 4) -neq 4;
+  if (!$IsBaseline) {
+    $IsBaseline = !( `
+      Add-Type -MemberDefinition '[DllImport("kernel32.dll")] public static extern bool IsProcessorFeaturePresent(int ProcessorFeature);' `
+        -Name 'Kernel32' -Namespace 'Win32' -PassThru `
+    )::IsProcessorFeaturePresent(40);
+  }
 
   $BunRoot = if ($env:BUN_INSTALL) { $env:BUN_INSTALL } else { "${Home}\.bun" }
   $BunBin = mkdir -Force "${BunRoot}\bin"
 
+  try {
+    Remove-Item "${BunBin}\bun.exe" -Force
+  } catch [System.Management.Automation.ItemNotFoundException] {
+    # ignore
+  } catch [System.UnauthorizedAccessException] {
+    $openProcesses = Get-Process -Name bun | Where-Object { $_.Path -eq "${BunBin}\bun.exe" }
+    if ($openProcesses.Count -gt 0) {
+      Write-Output "Install Failed - An older installation exists and is open. Please close open Bun processes and try again."
+      exit 1
+    }
+    Write-Output "Install Failed - An unknown error occurred while trying to remove the existing installation"
+    Write-Output $_
+    exit 1
+  } catch {
+    Write-Output "Install Failed - An unknown error occurred while trying to remove the existing installation"
+    Write-Output $_
+    exit 1
+  }
+
   $Target = "bun-windows-$Arch"
   if ($IsBaseline) {
     $Target = "bun-windows-$Arch-baseline"
@@ -72,12 +152,16 @@ function Install-Bun {
 
   $null = mkdir -Force $BunBin
   Remove-Item -Force $ZipPath -ErrorAction SilentlyContinue
+
+  # curl.exe is faster than PowerShell 5's 'Invoke-WebRequest'
+  # note: 'curl' is an alias to 'Invoke-WebRequest'. so the exe suffix is required
   curl.exe "-#SfLo" "$ZipPath" "$URL" 
   if ($LASTEXITCODE -ne 0) {
     Write-Output "Install Failed - could not download $URL"
     Write-Output "The command 'curl.exe $URL -o $ZipPath' exited with code ${LASTEXITCODE}`n"
     exit 1
   }
+
   if (!(Test-Path $ZipPath)) {
     Write-Output "Install Failed - could not download $URL"
     Write-Output "The file '$ZipPath' does not exist. Did an antivirus delete it?`n"
@@ -90,14 +174,14 @@ function Install-Bun {
     Expand-Archive "$ZipPath" "$BunBin" -Force
     $global:ProgressPreference = $lastProgressPreference
     if (!(Test-Path "${BunBin}\$Target\bun.exe")) {
-      throw "The file '${BunBin}\$Target\bun.exe' does not exist. Download is corrupt / Antivirus intercepted?`n"
+      throw "The file '${BunBin}\$Target\bun.exe' does not exist. Download is corrupt or intercepted Antivirus?`n"
     }
   } catch {
     Write-Output "Install Failed - could not unzip $ZipPath"
     Write-Error $_
     exit 1
   }
-  Remove-Item "${BunBin}\bun.exe" -ErrorAction SilentlyContinue
+
   Move-Item "${BunBin}\$Target\bun.exe" "${BunBin}\bun.exe" -Force
 
   Remove-Item "${BunBin}\$Target" -Recurse -Force
@@ -117,10 +201,10 @@ function Install-Bun {
     Install-Bun -Version $Version -ForceBaseline $True
     exit 1
   }
-  if (($LASTEXITCODE -eq 3221225781) # STATUS_DLL_NOT_FOUND
+  # '1073741515' was spotted in the wild, but not clearly documented as a status code:
   # https://discord.com/channels/876711213126520882/1149339379446325248/1205194965383250081
   # http://community.sqlbackupandftp.com/t/error-1073741515-solved/1305
-  || ($LASTEXITCODE -eq 1073741515))
+  if (($LASTEXITCODE -eq 3221225781) -or ($LASTEXITCODE -eq 1073741515)) # STATUS_DLL_NOT_FOUND
   { 
     Write-Output "Install Failed - You are missing a DLL required to run bun.exe"
     Write-Output "This can be solved by installing the Visual C++ Redistributable from Microsoft:`nSee https://learn.microsoft.com/cpp/windows/latest-supported-vc-redist`nDirect Download -> https://aka.ms/vs/17/release/vc_redist.x64.exe`n`n"
@@ -132,6 +216,16 @@ function Install-Bun {
     Write-Output "The command '${BunBin}\bun.exe --revision' exited with code ${LASTEXITCODE}`n"
     exit 1
   }
+
+  $env:IS_BUN_AUTO_UPDATE = "1"
+  $null = "$(& "${BunBin}\bun.exe" completions)"
+  # if ($LASTEXITCODE -ne 0) {
+  #   Write-Output "Install Failed - could not finalize installation"
+  #   Write-Output "The command '${BunBin}\bun.exe completions' exited with code ${LASTEXITCODE}`n"
+  #   exit 1
+  # }
+  $env:IS_BUN_AUTO_UPDATE = $null
+
   $DisplayVersion = if ($BunRevision -like "*-canary.*") {
     "${BunRevision}"
   } else {
@@ -141,18 +235,6 @@ function Install-Bun {
   $C_RESET = [char]27 + "[0m"
   $C_GREEN = [char]27 + "[1;32m"
 
-  # delete bunx if it exists already. this happens if you re-install
-  # we don't want to hit an "already exists" error.
-  Remove-Item "${BunBin}\bunx.exe" -ErrorAction SilentlyContinue
-  Remove-Item "${BunBin}\bunx.cmd" -ErrorAction SilentlyContinue
-
-  try {
-    $null = New-Item -ItemType HardLink -Path "${BunBin}\bunx.exe" -Target "${BunBin}\bun.exe" -Force
-  } catch {
-    Write-Warning "Could not create a hard link for bunx, falling back to a cmd script`n"
-    Set-Content -Path "${BunBin}\bunx.cmd" -Value "@%~dp0bun.exe x %*"
-  }
-
   Write-Output "${C_GREEN}Bun ${DisplayVersion} was installed successfully!${C_RESET}"
   Write-Output "The binary is located at ${BunBin}\bun.exe`n"
 
@@ -167,17 +249,36 @@ function Install-Bun {
     }
   } catch {}
 
-  $User = [System.EnvironmentVariableTarget]::User
-  $Path = [System.Environment]::GetEnvironmentVariable('Path', $User) -split ';'
-  if ($Path -notcontains $BunBin) {
-    $Path += $BunBin
-    [System.Environment]::SetEnvironmentVariable('Path', $Path -join ';', $User)
-  }
-  if ($env:PATH -notcontains ";${BunBin}") {
-    $env:PATH = "${env:Path};${BunBin}"
+  if (-not $NoRegisterInstallation) {
+    $rootKey = $null
+    try {
+      $RegistryKey = "HKCU:\Software\Microsoft\Windows\CurrentVersion\Uninstall\Bun"  
+      $rootKey = New-Item -Path $RegistryKey -Force
+      New-ItemProperty -Path $RegistryKey -Name "DisplayName" -Value "Bun" -PropertyType String -Force | Out-Null
+      New-ItemProperty -Path $RegistryKey -Name "InstallLocation" -Value "${BunRoot}" -PropertyType String -Force | Out-Null
+      New-ItemProperty -Path $RegistryKey -Name "DisplayIcon" -Value $BunBin\bun.exe -PropertyType String -Force | Out-Null
+      New-ItemProperty -Path $RegistryKey -Name "UninstallString" -Value "powershell -c `"& `'$BunRoot\uninstall.ps1`' -PauseOnError`"" -PropertyType String -Force | Out-Null
+    } catch {
+      if ($rootKey -ne $null) {
+        Remove-Item -Path $RegistryKey -Force
+      }
+    }
   }
 
   if(!$hasExistingOther) {
+    # Only try adding to path if there isn't already a bun.exe in the path
+    $Path = (Get-Env -Key "Path") -split ';'
+    if ($Path -notcontains $BunBin) {
+      if (-not $NoPathUpdate) {
+        $Path += $BunBin
+        Write-Env -Key 'Path' -Value ($Path -join ';')
+      } else {
+        Write-Output "Skipping adding '${BunBin}' to the user's %PATH%`n"
+      }
+    }
+
     Write-Output "To get started, restart your terminal/editor, then type `"bun`"`n"
   }
-}
\ No newline at end of file
+}
+
+Install-Bun -Version $Version -ForceBaseline $ForceBaseline
diff --git a/src/cli/install_completions_command.zig b/src/cli/install_completions_command.zig
index b0953d9b99fb9a..362f922b46f2c9 100644
--- a/src/cli/install_completions_command.zig
+++ b/src/cli/install_completions_command.zig
@@ -44,13 +44,10 @@ const ShellCompletions = @import("./shell_completions.zig");
 pub const InstallCompletionsCommand = struct {
     pub fn testPath(_: string) !std.fs.Dir {}
 
-    fn installBunxSymlink(allocator: std.mem.Allocator, cwd: []const u8) !void {
-        if (comptime Environment.isWindows) {
-            @panic("TODO on Windows");
-        }
+    const bunx_name = if (Environment.isDebug) "bunx-debug" else "bunx";
 
+    fn installBunxSymlinkPosix(allocator: std.mem.Allocator, cwd: []const u8) !void {
         var buf: [bun.MAX_PATH_BYTES]u8 = undefined;
-        const bunx_name = if (Environment.isDebug) "bunx-debug" else "bunx";
 
         // don't install it if it's already there
         if (bun.which(&buf, bun.getenvZ("PATH") orelse cwd, cwd, bunx_name) != null)
@@ -92,6 +89,81 @@ pub const InstallCompletionsCommand = struct {
         };
     }
 
+    fn installBunxSymlinkWindows(_: std.mem.Allocator, _: []const u8) !void {
+        // Because symlinks are not always allowed on windows,
+        // `bunx.exe` on windows is a hardlink to `bun.exe`
+        // for this to work, we need to delete and recreate the hardlink every time
+        const image_path = bun.windows.exePathW();
+        const image_dirname = image_path[0 .. (std.mem.lastIndexOfScalar(u16, image_path, '\\') orelse unreachable) + 1];
+
+        var bunx_path_buf: bun.WPathBuffer = undefined;
+
+        std.os.windows.DeleteFile(try bun.strings.concatBufT(u16, &bunx_path_buf, .{
+            &bun.windows.nt_object_prefix,
+            image_dirname,
+            comptime bun.strings.literal(u16, bunx_name ++ ".cmd"),
+        }), .{ .dir = null }) catch {};
+
+        const bunx_path_with_z = try bun.strings.concatBufT(u16, &bunx_path_buf, .{
+            &bun.windows.nt_object_prefix,
+            image_dirname,
+            comptime bun.strings.literal(u16, bunx_name ++ ".exe\x00"),
+        });
+        const bunx_path = bunx_path_with_z[0 .. bunx_path_with_z.len - 1 :0];
+        std.os.windows.DeleteFile(bunx_path, .{ .dir = null }) catch {};
+
+        if (bun.windows.CreateHardLinkW(bunx_path, image_path, null) == 0) {
+            // if hard link fails, use a cmd script
+            const script = "@%~dp0bun.exe x %*\n";
+
+            const bunx_cmd_with_z = try bun.strings.concatBufT(u16, &bunx_path_buf, .{
+                &bun.windows.nt_object_prefix,
+                image_dirname,
+                comptime bun.strings.literal(u16, bunx_name ++ ".exe\x00"),
+            });
+            const bunx_cmd = bunx_cmd_with_z[0 .. bunx_cmd_with_z.len - 1 :0];
+            // TODO: fix this zig bug, it is one line change to a few functions.
+            // const file = try std.fs.createFileAbsoluteW(bunx_cmd, .{});
+            const file = try std.fs.cwd().createFileW(bunx_cmd, .{});
+            defer file.close();
+            try file.writeAll(script);
+        }
+    }
+
+    fn installBunxSymlink(allocator: std.mem.Allocator, cwd: []const u8) !void {
+        if (Environment.isWindows) {
+            try installBunxSymlinkWindows(allocator, cwd);
+        } else {
+            try installBunxSymlinkPosix(allocator, cwd);
+        }
+    }
+
+    fn installUninstallerWindows() !void {
+        // This uninstaller file is only written if the current exe is within a path
+        // like `\bun\bin\<whatever>.exe` so that it probably only runs when the
+        // powershell `install.ps1` was used to install.
+
+        const image_path = bun.windows.exePathW();
+        const image_dirname = image_path[0..(std.mem.lastIndexOfScalar(u16, image_path, '\\') orelse unreachable)];
+
+        if (!std.mem.endsWith(u16, image_dirname, comptime bun.strings.literal(u16, "\\bun\\bin")))
+            return;
+
+        const content = @embedFile("uninstall.ps1");
+
+        var bunx_path_buf: bun.WPathBuffer = undefined;
+        const uninstaller_path = try bun.strings.concatBufT(u16, &bunx_path_buf, .{
+            &bun.windows.nt_object_prefix,
+            image_dirname[0 .. image_dirname.len - 3],
+            comptime bun.strings.literal(u16, "uninstall.ps1"),
+        });
+
+        const file = try std.fs.cwd().createFileW(uninstaller_path, .{});
+        defer file.close();
+
+        try file.writeAll(content);
+    }
+
     pub fn exec(allocator: std.mem.Allocator) !void {
         // Fail silently on auto-update.
         const fail_exit_code: u8 = if (bun.getenvZ("IS_BUN_AUTO_UPDATE") == null) 1 else 0;
@@ -120,9 +192,21 @@ pub const InstallCompletionsCommand = struct {
 
         installBunxSymlink(allocator, cwd) catch {};
 
+        if (Environment.isWindows) {
+            installUninstallerWindows() catch {};
+        }
+
+        // TODO: https://github.com/oven-sh/bun/issues/8939
+        if (Environment.isWindows) {
+            Output.errGeneric("PowerShell completions are not yet written for Bun yet.", .{});
+            Output.printErrorln("See https://github.com/oven-sh/bun/issues/8939", .{});
+            return;
+        }
+
         switch (shell) {
             .unknown => {
-                Output.prettyErrorln("<r><red>error:<r> Unknown or unsupported shell. Please set $SHELL to one of zsh, fish, or bash. To manually output completions, run this:\n      bun getcompletes", .{});
+                Output.errGeneric("Unknown or unsupported shell. Please set $SHELL to one of zsh, fish, or bash.", .{});
+                Output.note("To manually output completions, run 'bun getcompletes'", .{});
                 Global.exit(fail_exit_code);
             },
             else => {},
diff --git a/src/cli/run_command.zig b/src/cli/run_command.zig
index d3bf2526669bde..9eb484312cd4c9 100644
--- a/src/cli/run_command.zig
+++ b/src/cli/run_command.zig
@@ -610,15 +610,14 @@ pub const RunCommand = struct {
             const file_slice = target_path_buffer[0 .. prefix.len + len + file_name.len - "\x00".len];
             const dir_slice = target_path_buffer[0 .. prefix.len + len + dir_name.len];
 
-            const ImagePathName = std.os.windows.peb().ProcessParameters.ImagePathName;
-            std.debug.assert(ImagePathName.Buffer[ImagePathName.Length / 2] == 0); // trust windows
+            const image_path = bun.windows.exePathW();
 
             if (Environment.isDebug) {
                 // the link becomes out of date on rebuild
                 std.os.unlinkW(file_slice) catch {};
             }
 
-            if (bun.windows.CreateHardLinkW(@ptrCast(file_slice.ptr), @ptrCast(ImagePathName.Buffer), null) == 0) {
+            if (bun.windows.CreateHardLinkW(@ptrCast(file_slice.ptr), image_path.ptr, null) == 0) {
                 switch (std.os.windows.kernel32.GetLastError()) {
                     .ALREADY_EXISTS => {},
                     else => {
@@ -629,7 +628,7 @@ pub const RunCommand = struct {
                             target_path_buffer[dir_slice.len] = '\\';
                         }
 
-                        if (bun.windows.CreateHardLinkW(@ptrCast(file_slice.ptr), @ptrCast(ImagePathName.Buffer), null) == 0) {
+                        if (bun.windows.CreateHardLinkW(@ptrCast(file_slice.ptr), image_path.ptr, null) == 0) {
                             return;
                         }
                     },
diff --git a/src/cli/shell_completions.zig b/src/cli/shell_completions.zig
index 35f0ff00b94cf3..4df3eb70b831d6 100644
--- a/src/cli/shell_completions.zig
+++ b/src/cli/shell_completions.zig
@@ -15,6 +15,7 @@ pub const Shell = enum {
     bash,
     zsh,
     fish,
+    pwsh,
 
     const bash_completions = @import("root").completions.bash;
     const zsh_completions = @import("root").completions.zsh;
@@ -32,13 +33,17 @@ pub const Shell = enum {
     pub fn fromEnv(comptime Type: type, SHELL: Type) Shell {
         const basename = std.fs.path.basename(SHELL);
         if (strings.eqlComptime(basename, "bash")) {
-            return Shell.bash;
+            return .bash;
         } else if (strings.eqlComptime(basename, "zsh")) {
-            return Shell.zsh;
+            return .zsh;
         } else if (strings.eqlComptime(basename, "fish")) {
-            return Shell.fish;
+            return .fish;
+        } else if (strings.eqlComptime(basename, "pwsh") or
+            strings.eqlComptime(basename, "powershell"))
+        {
+            return .pwsh;
         } else {
-            return Shell.unknown;
+            return .unknown;
         }
     }
 };
diff --git a/src/cli/uninstall.ps1 b/src/cli/uninstall.ps1
new file mode 100644
index 00000000000000..df74be1872f7d2
--- /dev/null
+++ b/src/cli/uninstall.ps1
@@ -0,0 +1,112 @@
+# This script will remove the Bun installation at the location of this
+# script, removing it from %PATH%, deleting caches, and removing it from
+# the list of installed programs.
+param(
+  [switch]$PauseOnError = $false
+)
+
+$ErrorActionPreference = "Stop"
+
+# These two environment functions are roughly copied from https://github.com/prefix-dev/pixi/pull/692
+# They are used instead of `SetEnvironmentVariable` because of unwanted variable expansions.
+function Write-Env {
+  param([String]$Key, [String]$Value)
+
+  $EnvRegisterKey = Get-Item -Path 'HKCU:Environment'
+  if ($null -eq $Value) {
+    $EnvRegisterKey.DeleteValue($Key)
+  } else {
+    $RegistryValueKind = if ($Value.Contains('%')) {
+      [Microsoft.Win32.RegistryValueKind]::ExpandString
+    } elseif ($EnvRegisterKey.GetValue($Key)) {
+      $EnvRegisterKey.GetValueKind($Key)
+    } else {
+      [Microsoft.Win32.RegistryValueKind]::String
+    }
+    $EnvRegisterKey.SetValue($Key, $Value, $RegistryValueKind)
+  }
+}
+
+function Get-Env {
+  param([String] $Key)
+
+  $RegisterKey = Get-Item -Path 'HKCU:Environment'
+  $EnvRegisterKey.GetValue($Key, $null, [Microsoft.Win32.RegistryValueOptions]::DoNotExpandEnvironmentNames)
+}
+
+if (-not (Test-Path "${PSScriptRoot}\bin\bun.exe")) {
+  Write-Host "bun.exe not found in ${PSScriptRoot}\bin`n`nRefusing to delete this directory as it may.`n`nIf this uninstallation is still intentional, please just manually delete this folder."
+  if ($PauseOnError) { pause }
+  exit 1
+}
+
+function Stop-Bun {
+  try {
+    Get-Process -Name bun | Where-Object { $_.Path -eq "${PSScriptRoot}\bin\bun.exe" } | Stop-Process -Force
+  } catch [Microsoft.PowerShell.Commands.ProcessCommandException] {
+    # ignore
+  } catch {
+    Write-Host "There are open instances of bun.exe that could not be automatically closed."
+    if ($PauseOnError) { pause }
+    exit 1
+  }
+}
+
+# Remove ~\.bun\bin\bun.exe
+try {
+  Stop-Bun
+  Remove-Item "${PSScriptRoot}\bin\bun.exe" -Force
+} catch {
+  # Try a second time
+  Stop-Bun
+  Start-Sleep -Seconds 1
+  try {
+    Remove-Item "${PSScriptRoot}\bin\bun.exe" -Force
+  } catch {
+    Write-Host $_
+    Write-Host "`n`nCould not delete ${PSScriptRoot}\bin\bun.exe."
+    Write-Host "Please close all instances of bun.exe and try again."
+    if ($PauseOnError) { pause }
+    exit 1
+  }
+}
+
+# Remove ~\.bun
+try {
+  Remove-Item "${PSScriptRoot}" -Recurse -Force
+} catch {
+  Write-Host "Could not delete ${PSScriptRoot}."
+  if ($PauseOnError) { pause }
+  exit 1
+}
+
+# Delete some tempdir files. Do not fail if an error happens here
+try {
+  Remove-Item "${Temp}\bun-*" -Recurse -Force
+} catch {}
+try {
+  Remove-Item "${Temp}\bunx-*" -Recurse -Force
+} catch {}
+
+# Remove Entry from path
+try {
+  $Path = Get-Env -Key 'Path'
+  $Path = $Path -split ';'
+  $Path = $Path | Where-Object { $_ -ne "${PSScriptRoot}\bin" }
+  Write-Env -Key 'Path' -Value ($Path -join ';')
+} catch {
+  Write-Host "Could not remove ${PSScriptRoot}\bin from PATH."
+  if ($PauseOnError) { pause }
+  exit 1
+}
+
+# Remove Entry from Windows Installer, if it is owned by this installation.
+try {
+  $item = Get-Item "HKCU:\Software\Microsoft\Windows\CurrentVersion\Uninstall\Bun";
+  $location = $item.GetValue("InstallLocation");
+  if ($location -eq "${PSScriptRoot}") {
+    Remove-Item "HKCU:\Software\Microsoft\Windows\CurrentVersion\Uninstall\Bun" -Recurse
+  }
+} catch {
+  # unlucky tbh
+}
diff --git a/src/cli/upgrade_command.zig b/src/cli/upgrade_command.zig
index bfc0619b81a224..ba677b0b95cbd5 100644
--- a/src/cli/upgrade_command.zig
+++ b/src/cli/upgrade_command.zig
@@ -69,7 +69,7 @@ pub const Version = struct {
                             ),
                         ),
                     },
-                ) catch unreachable;
+                ) catch bun.outOfMemory();
             }
             return this.tag;
         }
@@ -117,13 +117,12 @@ pub const Version = struct {
 };
 
 pub const UpgradeCheckerThread = struct {
-    var update_checker_thread: std.Thread = undefined;
     pub fn spawn(env_loader: *DotEnv.Loader) void {
         if (env_loader.map.get("BUN_DISABLE_UPGRADE_CHECK") != null or
             env_loader.map.get("CI") != null or
             strings.eqlComptime(env_loader.get("BUN_CANARY") orelse "0", "1"))
             return;
-        update_checker_thread = std.Thread.spawn(.{}, run, .{env_loader}) catch return;
+        var update_checker_thread = std.Thread.spawn(.{}, run, .{env_loader}) catch return;
         update_checker_thread.detach();
     }
 
@@ -133,13 +132,14 @@ pub const UpgradeCheckerThread = struct {
         std.time.sleep(std.time.ns_per_ms * delay);
 
         Output.Source.configureThread();
-        HTTP.HTTPThread.init() catch unreachable;
+        try HTTP.HTTPThread.init();
 
         defer {
             js_ast.Expr.Data.Store.deinit();
             js_ast.Stmt.Data.Store.deinit();
         }
-        var version = (try UpgradeCommand.getLatestVersion(default_allocator, env_loader, undefined, undefined, false, true)) orelse return;
+
+        var version = (try UpgradeCommand.getLatestVersion(default_allocator, env_loader, null, null, false, true)) orelse return;
 
         if (!version.isCurrent()) {
             if (version.name()) |name| {
@@ -171,8 +171,8 @@ pub const UpgradeCommand = struct {
     pub fn getLatestVersion(
         allocator: std.mem.Allocator,
         env_loader: *DotEnv.Loader,
-        refresher: *std.Progress,
-        progress: *std.Progress.Node,
+        refresher: ?*std.Progress,
+        progress: ?*std.Progress.Node,
         use_profile: bool,
         comptime silent: bool,
     ) !?Version {
@@ -234,7 +234,7 @@ pub const UpgradeCommand = struct {
         var metadata_body = try MutableString.init(allocator, 2048);
 
         // ensure very stable memory address
-        var async_http: *HTTP.AsyncHTTP = allocator.create(HTTP.AsyncHTTP) catch unreachable;
+        var async_http: *HTTP.AsyncHTTP = try allocator.create(HTTP.AsyncHTTP);
         async_http.* = HTTP.AsyncHTTP.initSync(
             allocator,
             .GET,
@@ -250,7 +250,7 @@ pub const UpgradeCommand = struct {
         );
         async_http.client.reject_unauthorized = env_loader.getTLSRejectUnauthorized();
 
-        if (!silent) async_http.client.progress_node = progress;
+        if (!silent) async_http.client.progress_node = progress.?;
         const response = try async_http.sendSync(true);
 
         switch (response.status_code) {
@@ -268,8 +268,8 @@ pub const UpgradeCommand = struct {
         initializeStore();
         var expr = ParseJSON(&source, &log, allocator) catch |err| {
             if (!silent) {
-                progress.end();
-                refresher.refresh();
+                progress.?.end();
+                refresher.?.refresh();
 
                 if (log.errors > 0) {
                     if (Output.enable_ansi_colors) {
@@ -277,6 +277,7 @@ pub const UpgradeCommand = struct {
                     } else {
                         try log.printForLogLevelWithEnableAnsiColors(Output.errorWriter(), false);
                     }
+
                     Global.exit(1);
                 } else {
                     Output.prettyErrorln("Error parsing releases from GitHub: <r><red>{s}<r>", .{@errorName(err)});
@@ -288,9 +289,9 @@ pub const UpgradeCommand = struct {
         };
 
         if (log.errors > 0) {
-            if (comptime !silent) {
-                progress.end();
-                refresher.refresh();
+            if (!silent) {
+                progress.?.end();
+                refresher.?.refresh();
 
                 if (Output.enable_ansi_colors) {
                     try log.printForLogLevelWithEnableAnsiColors(Output.errorWriter(), true);
@@ -306,9 +307,9 @@ pub const UpgradeCommand = struct {
         var version = Version{ .zip_url = "", .tag = "", .buf = metadata_body, .size = 0 };
 
         if (expr.data != .e_object) {
-            if (comptime !silent) {
-                progress.end();
-                refresher.refresh();
+            if (!silent) {
+                progress.?.end();
+                refresher.?.refresh();
 
                 const json_type: js_ast.Expr.Tag = @as(js_ast.Expr.Tag, expr.data);
                 Output.prettyErrorln("JSON error - expected an object but received {s}", .{@tagName(json_type)});
@@ -326,8 +327,8 @@ pub const UpgradeCommand = struct {
 
         if (version.tag.len == 0) {
             if (comptime !silent) {
-                progress.end();
-                refresher.refresh();
+                progress.?.end();
+                refresher.?.refresh();
 
                 Output.prettyErrorln("JSON Error parsing releases from GitHub: <r><red>tag_name<r> is missing?\n{s}", .{metadata_body.list.items});
                 Global.exit(1);
@@ -380,8 +381,8 @@ pub const UpgradeCommand = struct {
         }
 
         if (comptime !silent) {
-            progress.end();
-            refresher.refresh();
+            progress.?.end();
+            refresher.?.refresh();
             if (version.name()) |name| {
                 Output.prettyErrorln("Bun v{s} is out, but not for this platform ({s}) yet.", .{
                     name, Version.triplet,
@@ -433,8 +434,6 @@ pub const UpgradeCommand = struct {
         };
         env_loader.loadProcess();
 
-        var version: Version = undefined;
-
         const use_canary = brk: {
             const default_use_canary = Environment.is_canary;
 
@@ -447,11 +446,11 @@ pub const UpgradeCommand = struct {
 
         const use_profile = strings.containsAny(bun.argv(), "--profile");
 
-        if (!use_canary) {
+        const version: Version = if (!use_canary) v: {
             var refresher = std.Progress{};
             var progress = refresher.start("Fetching version tags", 0);
 
-            version = (try getLatestVersion(ctx.allocator, &env_loader, &refresher, progress, use_profile, false)) orelse return;
+            const version = (try getLatestVersion(ctx.allocator, &env_loader, &refresher, progress, use_profile, false)) orelse return;
 
             progress.end();
             refresher.refresh();
@@ -482,14 +481,14 @@ pub const UpgradeCommand = struct {
                 Output.prettyErrorln("<r><b>Downgrading from Bun <blue>{s}-canary<r> to Bun <cyan>v{s}<r><r>\n", .{ Global.package_json_version, version.name().? });
             }
             Output.flush();
-        } else {
-            version = Version{
-                .tag = "canary",
-                .zip_url = "https://github.com/oven-sh/bun/releases/download/canary/" ++ Version.zip_filename,
-                .size = 0,
-                .buf = MutableString.initEmpty(bun.default_allocator),
-            };
-        }
+
+            break :v version;
+        } else Version{
+            .tag = "canary",
+            .zip_url = "https://github.com/oven-sh/bun/releases/download/canary/" ++ Version.zip_filename,
+            .size = 0,
+            .buf = MutableString.initEmpty(bun.default_allocator),
+        };
 
         const zip_url = URL.parse(version.zip_url);
         const http_proxy: ?URL = env_loader.getHttpProxy(zip_url);
@@ -498,7 +497,7 @@ pub const UpgradeCommand = struct {
             var refresher = std.Progress{};
             var progress = refresher.start("Downloading", version.size);
             refresher.refresh();
-            var async_http = ctx.allocator.create(HTTP.AsyncHTTP) catch unreachable;
+            var async_http = try ctx.allocator.create(HTTP.AsyncHTTP);
             var zip_file_buffer = try ctx.allocator.create(MutableString);
             zip_file_buffer.* = try MutableString.init(ctx.allocator, @max(version.size, 1024));
 
@@ -865,7 +864,7 @@ pub const UpgradeCommand = struct {
                     "completions",
                 };
 
-                env_loader.map.put("IS_BUN_AUTO_UPDATE", "true") catch unreachable;
+                env_loader.map.put("IS_BUN_AUTO_UPDATE", "true") catch bun.outOfMemory();
                 var buf_map = try env_loader.map.cloneToEnvMap(ctx.allocator);
                 _ = std.ChildProcess.run(.{
                     .allocator = ctx.allocator,
@@ -873,7 +872,7 @@ pub const UpgradeCommand = struct {
                     .cwd = target_dirname,
                     .max_output_bytes = 4096,
                     .env_map = &buf_map,
-                }) catch undefined;
+                }) catch {};
             }
 
             Output.printStartEnd(ctx.start_time, std.time.nanoTimestamp());
diff --git a/src/output.zig b/src/output.zig
index 78df0b8c9c0271..2c6160b80e3c47 100644
--- a/src/output.zig
+++ b/src/output.zig
@@ -829,7 +829,7 @@ fn scopedWriter() std.fs.File.Writer {
                     std.fs.cwd().fd,
                     path,
                     std.os.O.TRUNC | std.os.O.CREAT | std.os.O.WRONLY,
-                    0o644,
+                    if (Environment.isWindows) 0 else 0o644,
                 ) catch |err_| {
                     // Ensure we don't panic inside panic
                     Scoped.loaded_env = false;
diff --git a/src/string_immutable.zig b/src/string_immutable.zig
index 2cd489ee793752..62cf83aa8fb443 100644
--- a/src/string_immutable.zig
+++ b/src/string_immutable.zig
@@ -1033,8 +1033,8 @@ pub inline fn append(allocator: std.mem.Allocator, self: string, other: string)
     return buf;
 }
 
-pub inline fn joinAlloc(allocator: std.mem.Allocator, strs: anytype) ![]u8 {
-    const buf = try allocator.alloc(u8, len: {
+pub inline fn concatAllocT(comptime T: type, allocator: std.mem.Allocator, strs: anytype) ![]T {
+    const buf = try allocator.alloc(T, len: {
         var len: usize = 0;
         inline for (strs) |s| {
             len += s.len;
@@ -1042,28 +1042,24 @@ pub inline fn joinAlloc(allocator: std.mem.Allocator, strs: anytype) ![]u8 {
         break :len len;
     });
 
-    var remain = buf;
-    inline for (strs) |s| {
-        if (s.len > 0) {
-            @memcpy(remain, s);
-            remain = remain[s.len..];
-        }
-    }
-
-    return buf;
+    return concatBufT(T, buf, strs) catch |e| switch (e) {
+        error.NoSpaceLeft => unreachable, // exact size calculated
+    };
 }
 
-pub inline fn joinBuf(out: []u8, parts: anytype, comptime parts_len: usize) []u8 {
+pub inline fn concatBufT(comptime T: type, out: []T, strs: anytype) ![]T {
     var remain = out;
-    var count: usize = 0;
-    inline for (0..parts_len) |i| {
-        const part = parts[i];
-        bun.copy(u8, remain, part);
-        remain = remain[part.len..];
-        count += part.len;
+    var n: usize = 0;
+    inline for (strs) |s| {
+        if (s.len > remain.len) {
+            return error.NoSpaceLeft;
+        }
+        @memcpy(remain.ptr, s);
+        remain = remain[s.len..];
+        n += s.len;
     }
 
-    return out[0..count];
+    return out[0..n];
 }
 
 pub fn index(self: string, str: string) i32 {
diff --git a/src/windows.zig b/src/windows.zig
index df50b493dfb5f0..dcd57e14014333 100644
--- a/src/windows.zig
+++ b/src/windows.zig
@@ -3091,6 +3091,11 @@ pub extern "kernel32" fn OpenProcess(
 // https://learn.microsoft.com/en-us/windows/win32/procthread/process-security-and-access-rights
 pub const PROCESS_QUERY_LIMITED_INFORMATION: DWORD = 0x1000;
 
+pub fn exePathW() [:0]const u16 {
+    const image_path_unicode_string = &std.os.windows.peb().ProcessParameters.ImagePathName;
+    return image_path_unicode_string.Buffer[0 .. image_path_unicode_string.Length / 2 :0];
+}
+
 pub const KEY_EVENT_RECORD = extern struct {
     bKeyDown: BOOL,
     wRepeatCount: WORD,