Gawd I hate patching .NET… newly released tonight is a bundle of “known issues” for .NET updates including this gem:
Files in use or File Locks can Result in Framework Assembly Files being Deleted:
If the installation of framework patches fail and roll back due to assemblies in the GAC (Global Access Cache) being held “*/in use”/* or */locked/* you might find some assemblies being deleted
Updating assemblies that are *locked* or *in use”* might cause them to be inappropriately deleted. This is a bug. Microsoft is presently working on a fix.
Microsoft is aware of this problem and is expected to create a hotfix soon. This article will be updated when release information is known. This fix will address only the deletion of assemblies from the GAC. The failure of the patch must be addressed separately and will not be affected by this fix.
There are no known workarounds. If the problem and deleting of the files has not yet occurred the best approach is to reduce the risk of any patch installations from failing by shutting down any applications that might be locking files. See KB 2263996 “Patching of Microsoft Framework can fail with Access is denied or File in Use error” for steps to detect and prevent applications locking framework assembly files. See More Information section for instructions on how to counter the problem if it has already occurred.See More Information section for instructions on how to counter the problem if it has already occurred.
Geeze dudes… then don’t release the patch. This is where that lovely “we need patched out in 60 days” blows up for me.. I want solid good patches not ones that I read through the known issues and go “oh crap!”