No Apple icon/menu in menubar One of our Macs is still on Mac OS X 10.6.8 and on that particular Mac, every so often, there is no Apple icon. When this happens, there is no Apple menu either. What I mean is that clicking where the Apple icon should be results in nothing - no menu options at all.

Sadly, this behavior is unpredictable. It can occur immediately after booting up, or it can occur after days of heavy use. We haven't noticed any pattern whatsoever. :(

We have tried resetting the NVRAM and SMC, starting in Safe Mode, quitting the Finder, verifying/repairing permissions, and scanning for viruses.

None of these steps have fixed this problem. I do not recall seeing the Apple Menu disappear while in Safe Mode, but since this issue is not constant it could just be that the Mac hasn't been used in Safe Mode for long enough to occur.

MY QUESTIONS:


Has anyone ever anywhere seen this behavior before? 
Any suggestions beyond having to do a full clean install?
Your problem is located either inside WindowServer or Finder processes.

The problem might come from 3 different sources:


memory corruption (but this would strike on other programs)
application corruption and this might come from:


an old disk causing errors on one of this files upon heating
a corruption within one of these files showing up upon a large use of internal structures.



To identify a potential error on your disk (case 2.1) I advise you to run 
Disk Utility on mode Verify Disk many times so as to make it heat until the correct status eventually change.

To identify which program is running (case 2.2) when you see this bug, I advise you to run Activity Monitor and try to kill (with the button ✕) each of these programs to verify which one of the 2 is the culprit.
Once you identified it, you will have to replace it with a correct backup. If you don't have one, it will be easier to reinstall the System.

But don't do this as an automatic measure without first checking what is the original cause of your problem.