Blue Screen Win32k.sys 0x50

Yesterday we had one client lose 5 machines to a stop error when they rebooted. This is caused by a bad Microsoft update. Specifically, KB2982791 which updates fonts. If you search around there were previous issues cause by font updates and the font cache not being cleared properly.

Yesterday, we fixed up a couple of the machines by doing a system restore and delaying all updates because we were not sure of the cause. I'm now seeing postings that indicating that removing the font cache file may allow the system to boot. Delete this file:

• C:\Windows\System32\fntcache.dat

For your reference, this Microsoft forum with a post by Iaurens provides step by step instructions on how to recover by booting from a Windows 7 Install DVD.

• http://answers.microsoft.com/en-us/windows/forum/windows_7-windows_update/blue-screen-stop-0x50-after-applying-update/6da4d264-02d8-458e-89e2-a78fe68766fd?auth=1

Such a pity, we had just started doing auto approvals of updates for some clients again. I guess we'll move back to the manual approval mode so that we can delay updates like this that are likely to get pulled.

I should note that I don't think this is widespread as we've only had one client with the issue. Strangely it was their Engineering users with the issue. So, I'm guessing it's some type of software interaction causing the issue.

If you are using WSUS, I strongly suggest you decline KB2982791.

Update: Further reading suggests that KB2970228 is also bad and should be declined at this time.

Update, Aug 29/14: More drama. Apparently the replacement update for this also has some issues. Although less severe. Read someone else's rant here:

• http://www.infoworld.com/t/microsoft-windows/microsoft-ships-replacement-patch-kb-2993651-two-known-bugs-249342