diff --git a/mozilla/toolkit/mozapps/extensions/src/nsExtensionManager.js.in b/mozilla/toolkit/mozapps/extensions/src/nsExtensionManager.js.in
index 1e2b1a7cc24..5b4a769aafe 100644
--- a/mozilla/toolkit/mozapps/extensions/src/nsExtensionManager.js.in
+++ b/mozilla/toolkit/mozapps/extensions/src/nsExtensionManager.js.in
@@ -1553,7 +1553,13 @@ Installer.prototype = {
           "Failure exception: " + e);
       showMessage("malformedRegistrationTitle", [], "malformedRegistrationMessage",
                   [BundleManager.appName]);
+
+      var stageFile = this._installLocation.getStageFile(this._id);
+      if (stageFile)
+        this._installLocation.removeFile(stageFile);
+
       StartupCache.put(this._installLocation, this._id, OP_NEEDS_UNINSTALL, true);
+      StartupCache.write();
     }
   },
 
@@ -1611,7 +1617,13 @@ Installer.prototype = {
           "Failure exception: " + e);
       showMessage("malformedRegistrationTitle", [], "malformedRegistrationMessage",
                   [BundleManager.appName]);
+
+      var stageFile = this._installLocation.getStageFile(this._id);
+      if (stageFile)
+        this._installLocation.removeFile(stageFile);
+
       StartupCache.put(this._installLocation, this._id, OP_NEEDS_UNINSTALL, true);
+      StartupCache.write();
     }
   },
   
diff --git a/mozilla/xpinstall/src/nsSoftwareUpdateRun.cpp b/mozilla/xpinstall/src/nsSoftwareUpdateRun.cpp
index 6116cb5948d..7cf62f19ad1 100644
--- a/mozilla/xpinstall/src/nsSoftwareUpdateRun.cpp
+++ b/mozilla/xpinstall/src/nsSoftwareUpdateRun.cpp
@@ -501,6 +501,7 @@ extern "C" void RunInstallOnThread(void *data)
 #ifdef MOZ_XUL_APP
         if (NS_SUCCEEDED(hZip->Test("install.rdf")))
         {
+            hZip->Close();
             // appears to be an Extension Manager install
             nsIExtensionManager* em = installInfo->GetExtensionManager();
             if (em)