I had a customer running an older Dell 2950 server with windows 2008 and SQL 20012 that got this update. After the update the server would not fully boot and you would get a blank or black screen of death. At first I didn’t know what was happening. I though the boot process got corrupt. I was running chksdk and SFC repair checks. I ran just about every Microsoft boot repair utilities available with no fix. This customer did not have a server image or backup of this server. At the same the OS drive RAID 1 mirror primary drive failed so I was thinking file corruption. I had to manually restore the registry in C:\windows\system32\config just get into safe mode. From there I started looking logs and updates. I noticed KB449347 was installed the night before. I uninstalled KB449347 and the server reboots and goes into windows normally now. I’ve read other people are having this issue with certain antivirus. My customer was running Avast. Hopefull this helps somebody. I have about 8 hours into this trying to figure it out.
