Yesterday, I told you about KB3033929, one of the new updates Microsoft delivered this month. The update was actually offered back in October 2014 under a different KB number, but Microsoft had to remove it due to issues companies had with deploying it. This month, it's back, but listed under KB3033929. KB3033929 adds functionality for SHA-2 signing and verification due a weakness in SHA-1 for Windows 7 and Windows Server 2008 R2.
Yesterday, I also updated that article with news that some users were reporting problems. Installation would fail with an error code of 80004005 and then put computers into a reboot loop. Some news orgs reported it to be a catastrophic fail and that Microsoft should rescind the patch again. But, reports are varied. Some have had absolutely no problem with the update, while others – a minority – are experiencing the reported difficulty.
The issues seems to stem from specific configurations – possibly with systems that dual-boot or that have hard disk partitions that are not enabled. It's still not clear what causes the patch to go haywire or which specific configuration might cause it.
One thing is known. The problem seems to hit Windows 7 64 bit users the hardest. You can read through the customer reports in the Microsoft forums thread: Update KB3033929 fails with error code 80004005.
Add your comments there if you are experiencing the issue, and definitely let me know so we can figure out a solid reason together.
Again, KB3033929 just adds new capability, so it's not a critical install yet. If you fear you might experience trouble, delay installing it until things get sorted.