I have a default automatic login account, User A. The Dock renders all it is responsible for (Dock, Launchpad, Mission Control) correctly for User A, but when I Fast User Switch to User B or C or the Guest Account, the Dock process doesn’t render anything properly, as shown in the screenshot. The Dock and Launchpad do not have their backgrounds rendered This doesn’t happen when I disable automatic login and login to either User B, C or Guest on boot.

I did not have this problem on Lion.

If it matters, I have an Sapphire ATI Radeon 5450 HD.

Why is this happening and how do I fix it?

  • What do you mean "doesn't render anything properly"? I'm looking at the screen shot and can't seen anything wrong, but also don't know what I'm supposed to be looking for. Sep 17, 2012 at 11:08
  • Bottom half of Launchpad, The open folder and the Dock aren’t rendering their backgrounds properly.
    – duci9y
    Sep 17, 2012 at 11:37
  • a) that actually makes Launchpad look really cool :) but more importantly b) what happens if you killall Dock? Does it render correctly after you restart the Dock?
    – Ethan Lee
    Sep 22, 2012 at 5:32
  • Yes it does. That’s why it is NOT a hardware or driver issue.
    – duci9y
    Sep 22, 2012 at 5:53

2 Answers 2


Check for updates through the Mac App Store first just in case Apple may have fixed this (obviously not everyone is experiencing this issue, but they may have anyway). In the comments of this article about Mountain Lion bugs, many users are expressing the same issue that you are having, and having to logout and back in again to fix this.

Another thing you might try (if you haven't already) is to back up and re-install Mountain Lion.

update Everyone on this thread has the same exact issue. Yes, it is a bug, and yes, the only workaround is to killall Dock. I suggest using an AppleScript with Login Items, launchd, or Lingon (old, free, unsupported version here, and $3 newer, supported version here) to run killall Dock as soon as you log in so that the Dock just restarts itself immediately. Meanwhile, submit this bug to Apple.

  • Already reinstalled. And no updates for my Mac. I will look into that article.
    – duci9y
    Sep 23, 2012 at 6:50
  • Check Login items? Have you ever styled your dock? Try deleting com.apple.Dock.plist?
    – Ethan Lee
    Sep 23, 2012 at 7:18
  • No Login Items. Never styled the Dock. Been there, done that, still no go.
    – duci9y
    Sep 23, 2012 at 7:31
  • I've updated my answer. basically, apple needs to fix this in a future update. meanwhile, killall Dock on startup looks to be your only option
    – Ethan Lee
    Sep 23, 2012 at 8:08
  • You can create a simple applescript app that runs killall Dock during startup instead. Sep 23, 2012 at 8:11

Not much you can do about it, looks like a a driver or hardware bug with your specific video card.

Report it to Apple and wait/hope for them to fix the driver, or find a workaround (if it's a hardware bug).

Alternatively, buy a different video card or downgrade back to Lion.

  • As I mentioned, everything renders correctly on User A’s account. So it doesn’t seem to be a driver or hardware issue.
    – duci9y
    Sep 19, 2012 at 6:53

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