diff --git a/build.sc b/build.sc
index 7f0f6e100bb..f5b61d4c690 100755
--- a/build.sc
+++ b/build.sc
@@ -316,7 +316,10 @@ object dev extends MillModule{
     val classpath = runClasspath().map(_.path.toString)
     val args = forkArgs().distinct
     val (shellArgs, cmdArgs) =
-      if (!scala.util.Properties.isWin) (args, args)
+      if (!scala.util.Properties.isWin) (
+        Seq("-DMILL_CLASSPATH=" + classpath.mkString(":")) ++ args,
+        Seq("-DMILL_CLASSPATH=" + classpath.mkString(";")) ++ args
+      )
       else (
         Seq("""-XX:VMOptionsFile="$( dirname "$0" )"/mill.vmoptions"""),
         Seq("""-XX:VMOptionsFile=%~dp0\mill.vmoptions""")
@@ -345,6 +348,7 @@ def release = T{
   val dest = T.ctx().dest
   val filename = if (scala.util.Properties.isWin) "mill.bat" else "mill"
   val args = Seq(
+    "-DMILL_CLASSPATH=$0",
     "-DMILL_VERSION=" + publishVersion()._2,
     // Workaround for Zinc/JNA bug
     // https://github.com/sbt/sbt/blame/6718803ee6023ab041b045a6988fafcfae9d15b5/main/src/main/scala/sbt/Main.scala#L130
diff --git a/main/client/src/mill/main/client/MillClientMain.java b/main/client/src/mill/main/client/MillClientMain.java
index 17a043f6b67..e3d3ec6ea35 100644
--- a/main/client/src/mill/main/client/MillClientMain.java
+++ b/main/client/src/mill/main/client/MillClientMain.java
@@ -11,20 +11,8 @@
 
 public class MillClientMain {
     static void initServer(String lockBase, boolean setJnaNoSys) throws IOException,URISyntaxException{
-        ArrayList<String> selfJars = new ArrayList<String>();
-        ClassLoader current = MillClientMain.class.getClassLoader();
-        while(current != null){
-            if (current instanceof java.net.URLClassLoader) {
-                URL[] urls = ((java.net.URLClassLoader) current).getURLs();
-                for (URL url: urls) {
-                    selfJars.add(new File(url.toURI()).getCanonicalPath());
-                }
-            }
-            current = current.getParent();
-        }
-        if (Util.isJava9OrAbove) {
-            selfJars.addAll(Arrays.asList(System.getProperty("java.class.path").split(File.pathSeparator)));
-        }
+        String[] selfJars = System.getProperty("MILL_CLASSPATH").split(File.pathSeparator);
+
         ArrayList<String> l = new java.util.ArrayList<String>();
         l.add("java");
         Properties props = System.getProperties();
diff --git a/main/src/mill/main/RunScript.scala b/main/src/mill/main/RunScript.scala
index 50cbb213dae..aea66988364 100644
--- a/main/src/mill/main/RunScript.scala
+++ b/main/src/mill/main/RunScript.scala
@@ -39,6 +39,24 @@ object RunScript{
         instantiateInterpreter match{
           case Left((res, watched)) => (res, watched)
           case Right(interp) =>
+            val mainThread = Thread.currentThread()
+            val allClassloaders = {
+              val all = mutable.Buffer.empty[ClassLoader]
+              var current = mainThread.getContextClassLoader
+              while(current != null){
+                all.append(current)
+                current = current.getParent
+              }
+              all
+            }
+
+            log.outputStream.println(pprint.apply(allClassloaders, height = 9999))
+            log.outputStream.println(pprint.apply(
+              allClassloaders
+                .collect{case cl: java.net.URLClassLoader => cl -> cl.getURLs.filter(_.getProtocol == "file")},
+                height = 9999
+            ))
+//            log.outputStream.println(pprint.apply(SpecialClassLoader.initialClasspathSignature(mainThread.getContextClassLoader), height = 9999))
             interp.watch(path)
             val eval =
               for(rootModule <- evaluateRootModule(wd, path, interp, log))
@@ -76,6 +94,7 @@ object RunScript{
                          log: Logger
                         ): Res[mill.define.BaseModule] = {
 
+    log.info("RunScript.evaluateRootModule")
     val (pkg, wrapper) = Util.pathToPackageWrapper(Seq(), path relativeTo wd)
 
     for {
diff --git a/scratch/build.sc b/scratch/build.sc
index 9ee78d63c0b..ae763e4d767 100644
--- a/scratch/build.sc
+++ b/scratch/build.sc
@@ -1,3 +1,3 @@
 def thingy = T {
-  1234567
+  12345678
 }
\ No newline at end of file