Corporate environment running Macintosh OSX 10.6.8 and Firefox 7.0.1. Zimbra webmail web page loaded and works as long as user is using Firefox. When user steps away for a bit (maybe 10-50mins) they return to Firefox spinning beachball. I don't think this happens every time they step away. Also window was open at time of crash from Quicktime "Additional software is required for Quicktime to playback this media. It may be available from the Quicktime Components page." There are no additional components and there is no media on the page. This is what was available in console around the time of the error: 11/29/11 11:52:26 AM [0x0-0x11011].org.mozilla.firefox[208] Tue Nov 29 11:52:26 hlc1130.hlcommission.org firefox[208] <Error>: kCGErrorInvalidOperation: _CGSFindSharedWindow: WID 42 11/29/11 11:52:26 AM [0x0-0x11011].org.mozilla.firefox[208] Tue Nov 29 11:52:26 hlc1130.hlcommission.org firefox[208] <Error>: kCGErrorFailure: Set a breakpoint @ CGErrorBreakpoint() to catch errors as they are logged. 11/29/11 11:52:26 AM [0x0-0x11011].org.mozilla.firefox[208] Tue Nov 29 11:52:26 hlc1130.hlcommission.org firefox[208] <Error>: kCGErrorInvalidOperation: _CGSFindSharedWindow: WID 41 11/29/11 11:52:26 AM [0x0-0x11011].org.mozilla.firefox[208] Tue Nov 29 11:52:26 hlc1130.hlcommission.org firefox[208] <Error>: kCGErrorInvalidOperation: _CGSFindSharedWindow: WID 42 11/29/11 11:52:26 AM [0x0-0x11011].org.mozilla.firefox[208] Tue Nov 29 11:52:26 hlc1130.hlcommission.org firefox[208] <Error>: kCGErrorInvalidOperation: _CGSFindSharedWindow: WID 41 11/29/11 12:16:57 PM com.apple.launchd.peruser.471951236[153] ([0x0-0x11011].org.mozilla.firefox[208]) Exited: Terminated 11/29/11 12:17:02 PM firefox[334] *** __NSAutoreleaseNoPool(): Object 0x100504cd0 of class NSCFString autoreleased with no pool in place - just leaking 11/29/11 12:17:02 PM firefox[334] *** __NSAutoreleaseNoPool(): Object 0x100502210 of class NSCFNumber autoreleased with no pool in place - just leaking