I generally don't rely on AU for patch management. I hand job all my servers and our Desktop side uses SMS to roll out only some of the hotfixes. We have seen several problems brought about by some of the hotfixes and I can't see how companies can just throw caution to the wind and turn on AU.
That said, I do have AU turned on for my PC because, A) I want to test all hotfixes and B) with my admin rights, I should be better protected.
In a lapse of good judgement, I had turned on AU on my MS Proxy 2 server and today it bit me. At this juncture, I surmise that KB867801 was the cause of MS Proxy 2 failing. Uninstalling failed to rollback the WININET.DLL so I had to bring up the server in safe mode and replace it manually.
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Give a man a fish and he will be back for more. Slap him with a fish and he will go away forever.