diff --git a/tools/tests/old.js b/tools/tests/old.js
index e1cf2ce9de..34900e6677 100644
--- a/tools/tests/old.js
+++ b/tools/tests/old.js
@@ -22,7 +22,7 @@ var maybeFixRelease = function (env) {
 var runOldTest = function (filename, extraEnv) {
   var s = new Sandbox;
   var run = new Run(process.execPath, {
-    args: [files.pathResolve(__dirname, 'old', filename)],
+    args: [files.convertToOSPath(files.pathResolve(__dirname, 'old', filename))],
     env: maybeFixRelease(_.extend({
       METEOR_TOOL_PATH: s.execPath
     }, extraEnv))
diff --git a/tools/tests/old/test-bundler-assets.js b/tools/tests/old/test-bundler-assets.js
index a4962afd89..bc7bb4cc57 100644
--- a/tools/tests/old/test-bundler-assets.js
+++ b/tools/tests/old/test-bundler-assets.js
@@ -126,8 +126,9 @@ var runTest = function () {
     var cp = require('child_process');
     var meteor = process.env.METEOR_TOOL_PATH;
     var fut = new Future();
+
     // use a non-default port so we don't fail if someone is running an app now
-    var proc = cp.spawn(meteor, ["--once", "--port", "4123"], {
+    var proc = cp.exec([files.convertToOSPath(meteor), "--once", "--port", "4123"].join(' '), {
       cwd: projectContext.projectDir,
       stdio: 'inherit'
     });