Data Loss through WindowServer Crashes in Leopard

March 11th, 2009

Fortunately, Mac OS X put an end to those dreaded times when your Mac would crash at least once daily, with all unsaved work lost. That is, almost. At least for me, the issue is back after I upgraded to Leopard in fall, even if the crash frequency is “only” once every one to two weeks.

The symptom is always the same: when typing away in a Carbon (Rosetta?) application on my MacBook Pro, the screen freezes for a few seconds and then goes blue, while the WindowServer starts up again, presenting me with a login window. No need to say that the WindowServer takes all currently open applications with it, in effect trashing all unsaved work.

Digging in /Library/Logs/CrashReporter/ reveals that the crash always happens at the same location somewhere in CarbonCore:

Date/Time:       2009-03-10 17:00:46.770 +0100
OS Version:      Mac OS X 10.5.6 (9G55)
Report Version:  6

Exception Codes: KERN_PROTECTION_FAILURE at 0x00000000be255460
Crashed Thread:  0

Thread 0 Crashed:
0   ...ple.CoreServices.CarbonCore  0x94a47719 UCKeyTranslate + 363
1          0x929e8937 CGSUniCodeForKeyAndFlags + 152
2          0x928baee6 CGXCheckForHotKey + 499
3          0x9288b416 sPostContinuation + 1759
4          0x929de924 postAfterTapID + 266
5          0x929df88b postFilteredEventTapData + 496
6          0x92910ac7 _XPostFilteredEventTapData + 221
7          0x92810967 CGXWindowServer_server + 117
8          0x9289bc3b rendezvousHandler + 155
9          0x9288c70e CGXPostPortData + 158
10          0x9288c504 CGXRunOneServerPass + 556
11          0x92888b0f CGXRunOneServicesPass + 377
12          0x92893e9e CGXServerLoop + 161
13          0x92821fb9 CGXGetRootAdminCredentials + 0
14  WindowServer                    0x00001ff4 main + 24
15  WindowServer                    0x00001fbe start + 54

So far, I’ve only experienced the crash while I was working in Excel 2004 or Eudora, both Carbon PPC applications that run under Rosetta emulation.

I filed the bug with Apple on 2008-12-05 as rdar://6423987, also see the OpenRadar copy. It was acknowledged as a duplicate of rdar://5432883; Apple says engineering is still investigating.

It seems this bug is somewhat widespread and old (at least going back to December 2007). I could find the following reports that are probably describing the same issue:

Now this sort of bug is extremely exasperating, as it is bound to lead to data loss. Have you experienced the same issue? Please comment below, and, most importantly, file a bug at in which you mention the original Radar ID (5432883) so that Apple gets an idea how widespread the issue actually is.

Categories: hacking, macosx

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20 Comments Add your own

  • 1. Mike  |  April 20th, 2009 at 23:36

    I too have had the issue. And as you have found, there are many complaints, but no answers. I feel it has to do with Excel 2004 ,or maybe your suggestion of Rosetta is more accurate.

    Here is my post at Apple discussion pages:

    10.5.7 any day now…..


  • 2. plasticsfuture Data Loss &hellip  |  June 8th, 2009 at 03:21

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  • 3. Ryan Rickerts  |  June 16th, 2009 at 00:35

    I have been able to track this behavior down on our app that runs via Rosetta, namely 4D 2004. It is a hotkey their design framework assigns to Select All in the Edit menu (a natural default, I suppose), but something in the mapping is crashing WindowServer. If I make that selection directly (via point-click in the Menu) on the same screen, it does not crash.

    Only solution I have right now is to unassign the hotkey, or upgrade our application to the latest 4D version which is Intel native. Lots of problems with Rosetta coming up, so I would say the latter option is the best long-term solution.

  • 4. Ryan Rickerts  |  June 16th, 2009 at 18:50

    Upon further testing, I cannot conclusively say it is the Cmd-A keystroke. It seems to be some sequence of keystrokes following the use of the Command key, but I cannot reliably duplicate it.

  • 5. James Wright  |  July 14th, 2009 at 00:24

    Hey, I found a solution that worked for me. Not sure if it will apply to you.

    We recently upgraded a few of our workstations to MacPros with OS 10.5 and the Intel chips. One of our users had the same exact problem, seemingly to be related to Excel (also running 2004). She would be working on it and then find herself with the blue screen, then login screen.

    Turned out – It was her desktop background.

    Her background changes every hour, and when I noticed that her machine was misbehaving the same minute of each hour I asked her if she changed something to her desktop backgrounds. Turns out she changed it to “random” today, and once I unchecked “random” her machine has been rock solid.

    Sooo maybe check your Desktop & Screen saver options and make sure that “random” isn’t selected for change picture.

  • 6. Davidf H  |  September 5th, 2009 at 15:58

    Started getting these on my MacBook Pro out of the blue – Snow Leopard. I’ve been using Eudora for decades, and now, all of a sudden, crashes at least once a day. Extremely frustrating. I’m at a loss to determine what I changed – same static desktop, same apps, etc etc. I must have done something but no idea what.

    I have two bugs in – will suggest they get dupped. However, given that Rosetta is on the way out, this is extremely unlikely to ever get fixed…


  • 7. Davidf H  |  September 10th, 2009 at 02:48

    I just posted this to the Apple listserver thread:

    I posted earlier on how this probably relates to the Eudora problem I’m having. Well, I’ve got a lot more information. It seems it happens with several Carbon apps. Please note that Apple did NOT disable Carbon apps – they are still suppose to run. What I’ve found is a way to detect the symptom, but not offer a cure.

    Most of the crashes to date have occurred in a routine called UCKeyTranslate. Anyone can with ease determine if this is where your crash occurred. When you get the blue screen, open the Console App (in Utilities), make sure you have the list of files to examine on the left (Make sure toolbar button “Show Log List” is clicked on. Open the “System Diagnostic Reports” list, and see if there is a WIndowServer… entry at the bottom – if so click on it. About to lines down you should see something like this:

    Thread 0 Crashed: Dispatch queue: 0 …ple.CoreServices.CarbonCore 0×00007fff8735d2a6 UCKeyTranslate + 464

    The first line after “Crashed” is the key – here you can see the UCKeyTranslate. Now, I know this is where the windowserver crashed.

    If you see that. now click on system.log – its under the FILES container in the left list. In the search field enter UCKeyTranslate – if you see many entries, then you have this Carbon problem. I have a friend who runs the same app with no problem, so no idea what is different on my system. However, what I did was a fresh Snow Leopard install on a new partition, then I used Migration Assistant to move my apps from the Leopard partition to Snow Leopard.

    I’m an old time UNIX programmer, so what I did was write a small shell program to monitor system.log all the time, and to beep when this UCKeyTranslate error happens – so I can try and figure out what I do that is causing it. Unfortunately, it happens at random times and with no apparent pattern. But do note that I’ve gotten Excel 2004 and TextWrangler to cause these errors in addition to Eudora (which I use all the time). I infer from this that the problem is Carbon related, not Rosetta.

    I’m not sure how fonts could be related to this, but for sure they could be.

    If you’re having blue screens with Excel, look at the cause, and help interested parties determine if its this or some other persistent error causing the crashes.

  • 8. Davidf H  |  September 10th, 2009 at 23:18

    Good news! Apple just contacted me – this is a “known issue” and “we’re working on it”!

  • 9. gmk  |  September 11th, 2009 at 13:10

    Same problem here, happens only randomly in Excel 2004 since Snow Leopard when trying to type a capital letter with the Shift key. Before Snow Leopard, I had some problems (key strokes with no answers in Excel), but never a Window Server crash. Filled rdr://7215724 before I saw this post.

  • 10. topspin  |  September 21st, 2009 at 22:45

    Same problem here. Had the problem only with Excel (all other apps were fine) running on Leopard until I installed SL last week. Now both Excel and Entourage cause the problem described here, with the same diagnostic reports as described above. Argh – c’mon apple, at least get word out on your support site.

  • 11. pjp  |  September 29th, 2009 at 04:30

    Wondering what keyboard everyone is using, and if people have more than one input method selected in the “Input Sources” pane of the International/Language & Text System Preferences. (Including the Keyboard and Character Viewer”pane.)

    I’m having this issue on a Mac Pro with an Apple Keyboard (A1243) US. Just disabled Keyboard & Character Viewer. Now only using US keyboard layout.

    Also, anyone here using the Command-Space/Command=Option-Space key combo for anything that might cause you to inadvertently select any of these alternate input methods?

  • 12. Peter Russell  |  October 6th, 2009 at 17:58

    I was having this problem in several apps under Rosetta, until I disconnected my external monitor. Which sort of fits a windowserver crash.

  • 13. Tristan Lawrence  |  October 7th, 2009 at 16:53

    I am having the same UCKeyTranslate issue, with Word 2004 under Snow Leopard.

    The system log entry says:

    UCKeyTranslate – uchr may be corrupt, keyModifiersToTableNumFormat 4B74

    Does anybody know what “uchr” is and how I can un-corrupt it?

  • 14. Kedrick Ridges  |  October 13th, 2009 at 20:30

    I too discovered the problem on my new MacbookPro with Leopard when I installed and began using Excel 2004. I would be typing an entry in any field and poof—blue screen and login window. Very frustrating. I uninstalled and reinstalled Office 2004, and I haven’t seen the blue screen, but now my machine just freezes solid every once in awhile (when I’m using Excel), requiring a hard manual restart. Does anyone know if the problem goes away with Office 2007 for Mac?

  • 15. maurits  |  October 13th, 2009 at 21:15

    Yes, using Office 2008 mitigates the problem, since it runs natively (not under Rosetta). Native Intel apps are not affected.

  • 16. Michael Edward  |  November 24th, 2009 at 20:15

    I’m glad to see I’m not alone… I hope this problem can be fixed. I’ve experienced this problem since I installed Snow Leopard, when using Excel 2004. It crashes many times a day, to the point I decided to enter data to each cell and save!

  • 17. pjp  |  December 3rd, 2009 at 19:45

    Just a follow-up; this appears to finally be resolved in the OS X 10.6.2 update, at least for me.

  • 18. plasticsfuture » Mi&hellip  |  December 7th, 2009 at 01:38

    [...] Recently, I upgraded to Microsoft Office for Mac 2008 from the 2004 edition. Overall, it turned out to be a welcome improvement, amongst others because it doesn’t crash the WindowServer any more. [...]

  • 19. Kirk Jay Richards  |  February 16th, 2010 at 04:29

    Blue screen problem here. Happens when running Excel in MacBook Pro with 2nd monitor attached. Keyboard goes intermittantly inop in Excel. After a few intervals of this, blue-screen logout. I do see UCKeyTranslate in WindowServer log… Many entries:

    Feb 15 19:24:08 [57] kCGErrorIllegalArgument: Failure: UCKeyTranslate returns -50

    I’ve never seen the problem without the 2nd monitor. I’m on Leopard 10.5.8

  • 20. macinfo  |  May 12th, 2011 at 22:37

    Have the same problem with my Santa Rosa MacBook Pro 2.2 GHz from 2007.

    I can’t remember to have experienced this issue under OS X 10.5.8. Now with OS X 10.6 to 10.6.7 I almost encounter one WindowServer crash per day.

    It always seems to happen when there is much graphical data to process, like flash videos playing, switching Safari windows and tabs, Screen Saver activation, like those things.

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