diff --git a/source/dub/package_.d b/source/dub/package_.d
index d1234dd468..0c1fb7c3c7 100644
--- a/source/dub/package_.d
+++ b/source/dub/package_.d
@@ -598,38 +598,45 @@ class Package {
 
 private string determineVersionFromSCM(Path path)
 {
-	import std.file : exists, readText;
-
-	// quickly determine head commit without invoking GIT
-	string head_commit;
-	auto hpath = (path ~ ".git/HEAD").toNativeString();
-	if (exists(hpath)) {
-		auto head_ref = readText(hpath).strip();
-		if (head_ref.startsWith("ref: ")) {
-			auto rpath = (path ~ (".git/"~head_ref[5 .. $])).toNativeString();
-			if (exists(rpath))
-				head_commit = readText(rpath).strip();
+	// On Windows, which is slow at running external processes,
+	// cache the version numbers that are determined using
+	// GIT to speed up the initialization phase.
+	version (Windows) {
+		import std.file : exists, readText;
+
+		// quickly determine head commit without invoking GIT
+		string head_commit;
+		auto hpath = (path ~ ".git/HEAD").toNativeString();
+		if (exists(hpath)) {
+			auto head_ref = readText(hpath).strip();
+			if (head_ref.startsWith("ref: ")) {
+				auto rpath = (path ~ (".git/"~head_ref[5 .. $])).toNativeString();
+				if (exists(rpath))
+					head_commit = readText(rpath).strip();
+			}
 		}
-	}
 
-	// return the last determined version for that commit
-	// not that this is not always correct, most notably when
-	// a tag gets added/removed/changed and changes the outcome
-	// of the full version detection computation
-	auto vcachepath = path ~ ".dub/version.json";
-	if (existsFile(vcachepath)) {
-		auto ver = jsonFromFile(vcachepath);
-		if (head_commit == ver["commit"].opt!string)
-			return ver["version"].get!string;
+		// return the last determined version for that commit
+		// not that this is not always correct, most notably when
+		// a tag gets added/removed/changed and changes the outcome
+		// of the full version detection computation
+		auto vcachepath = path ~ ".dub/version.json";
+		if (existsFile(vcachepath)) {
+			auto ver = jsonFromFile(vcachepath);
+			if (head_commit == ver["commit"].opt!string)
+				return ver["version"].get!string;
+		}
 	}
 
 	// if no cache file or the HEAD commit changed, perform full detection
 	auto ret = determineVersionWithGIT(path);
 
-	// update version cache file
-	if (head_commit.length) {
-		if (!existsFile(path ~".dub")) createDirectory(path ~ ".dub");
-		atomicWriteJsonFile(vcachepath, Json(["commit": Json(head_commit), "version": Json(ret)]));
+	version (Windows) {
+		// update version cache file
+		if (head_commit.length) {
+			if (!existsFile(path ~".dub")) createDirectory(path ~ ".dub");
+			atomicWriteJsonFile(vcachepath, Json(["commit": Json(head_commit), "version": Json(ret)]));
+		}
 	}
 
 	return ret;