diff --git a/clientserver/src/mill/clientserver/Client.java b/clientserver/src/mill/clientserver/Client.java
index e2a92f7fb55..c4cbc265f51 100644
--- a/clientserver/src/mill/clientserver/Client.java
+++ b/clientserver/src/mill/clientserver/Client.java
@@ -25,7 +25,7 @@ static void initServer(String lockBase, boolean setJnaNoSys) throws IOException,
             }
             current = current.getParent();
         }
-        if (!System.getProperty("java.specification.version").startsWith("1.")) {
+        if (ClientServer.isJava9OrAbove) {
             selfJars.addAll(Arrays.asList(System.getProperty("java.class.path").split(File.pathSeparator)));
         }
         ArrayList<String> l = new java.util.ArrayList<String>();
@@ -166,14 +166,15 @@ public ClientOutputPumper(InputStream src, OutputStream dest1, OutputStream dest
         this.dest2 = dest2;
     }
 
-    boolean running = true;
     public void run() {
         byte[] buffer = new byte[1024];
         int state = 0;
-        try {
-            while(running){
-
+        boolean running = true;
+        boolean first = true;
+        while (running) {
+            try {
                 int n = src.read(buffer);
+                first = false;
                 if (n == -1) running = false;
                 else {
                     int i = 0;
@@ -197,12 +198,21 @@ public void run() {
                     dest1.flush();
                     dest2.flush();
                 }
+            } catch (IOException e) {
+                // Win32NamedPipeSocket input stream somehow doesn't return -1,
+                // instead it throws an IOException whose message contains "ReadFile()".
+                // However, if it throws an IOException before ever reading some bytes,
+                // it could not connect to the server, so exit.
+                if (ClientServer.isWindows && e.getMessage().contains("ReadFile()")) {
+                    if (first) {
+                        System.err.println("Failed to connect to server");
+                        System.exit(1);
+                    } else running = false;
+                } else {
+                    e.printStackTrace();
+                    System.exit(1);
+                }
             }
-        }catch(IOException e){
-            // Win32NamedPipeSocket input stream somehow doesn't return -1,
-            // but throw IOException whose message contains "ReadFile()" with a ccode
-            if (ClientServer.isWindows && e.getMessage().contains("ReadFile()")) running = false;
-            else throw new RuntimeException(e);
         }
     }
 
diff --git a/clientserver/src/mill/clientserver/ClientServer.java b/clientserver/src/mill/clientserver/ClientServer.java
index 7af5845b607..e2e63dcffc0 100644
--- a/clientserver/src/mill/clientserver/ClientServer.java
+++ b/clientserver/src/mill/clientserver/ClientServer.java
@@ -5,8 +5,9 @@
 import java.io.InputStream;
 import java.io.OutputStream;
 
-class ClientServer {
+public class ClientServer {
     public static boolean isWindows = System.getProperty("os.name").toLowerCase().startsWith("windows");
+    public static boolean isJava9OrAbove = !System.getProperty("java.specification.version").startsWith("1.");
 
     // Windows named pipe prefix (see https://github.com/sbt/ipcsocket/blob/v1.0.0/README.md)
     // Win32NamedPipeServerSocket automatically adds this as a prefix (if it is not already is prefixed),
diff --git a/core/src/mill/util/ClassLoader.scala b/core/src/mill/util/ClassLoader.scala
index 9f0a7ab3642..9678989e4b4 100644
--- a/core/src/mill/util/ClassLoader.scala
+++ b/core/src/mill/util/ClassLoader.scala
@@ -52,12 +52,7 @@ object ClassLoader {
 
   private def makeUrls(urls: Seq[URL])(implicit ctx: Ctx.Home): Seq[URL] = {
     if (ammonite.util.Util.java9OrAbove) {
-
-      val rtFile = ctx.home / io.github.retronym.java9rtexport.Export.rtJarName
-      if (!exists(rtFile)) {
-        cp(Path(Export.rt()), rtFile)
-      }
-      urls :+ rtFile.toNIO.toUri.toURL
+      urls :+ Export.rtAt(ctx.home.toIO).toURI.toURL
     } else {
       urls
     }
diff --git a/main/src/mill/Main.scala b/main/src/mill/Main.scala
index 0844e485f13..e026dfe0ef9 100644
--- a/main/src/mill/Main.scala
+++ b/main/src/mill/Main.scala
@@ -5,6 +5,7 @@ import java.io.{InputStream, PrintStream}
 import ammonite.main.Cli._
 import ammonite.ops._
 import ammonite.util.Util
+import io.github.retronym.java9rtexport.Export
 import mill.eval.Evaluator
 import mill.util.DummyInputStream
 
@@ -118,6 +119,14 @@ object Main {
             stateCache
           )
 
+          if (mill.clientserver.ClientServer.isJava9OrAbove) {
+            val rt = cliConfig.home / Export.rtJarName
+            if (!exists(rt)) {
+              runner.printInfo(s"Preparing Java ${System.getProperty("java.version")} runtime; this may take a minute or two ...")
+              Export.rtTo(rt.toIO, false)
+            }
+          }
+
           if (repl){
             runner.printInfo("Loading...")
             (runner.watchLoop(isRepl = true, printing = false, _.run()), runner.stateCache)
diff --git a/scalalib/src/mill/scalalib/ScalaModule.scala b/scalalib/src/mill/scalalib/ScalaModule.scala
index fdc83cbf09c..dc39a4a8982 100644
--- a/scalalib/src/mill/scalalib/ScalaModule.scala
+++ b/scalalib/src/mill/scalalib/ScalaModule.scala
@@ -330,7 +330,7 @@ trait ScalaModule extends mill.Module with TaskModule { outer =>
   }
 
   def ammoniteReplClasspath = T{
-    resolveDeps(T.task{Agg(ivy"com.lihaoyi:::ammonite:1.1.0-3-73d5734")})()
+    resolveDeps(T.task{Agg(ivy"com.lihaoyi:::ammonite:1.1.0-7-33b728c")})()
   }
   def repl() = T.command{
     if (T.ctx().log.inStream == DummyInputStream){