Last Tuesday Microsoft issued their August updates for fixes and security, unfortunately it renders Windows 8.1 completely to un-bootable for a lot of end-users as they end up with a black failure screen. The issue resides in two updated files. On the Microsoft support forum it rains complaints about the so called August update. Read more after the break.
Users that have a system restore point enabled can retrieve access to the OS in the pre-update state and get Windows going again. Those that have system restore disabled are in a world of hurt and might have to reside to a system OS backup, or revert to a clean install. For those with a system restore point, please make sure that you uninstall the following updates: KB2982791 and the optional update KB2975719 as these are the two responsible for all this.
The problem identifies itself (for those affected) after your system has had two reboots after installing the August update. Microsoft explains that the problems are being investigated and that they are looking for a solution with the team responsible for the KB2982791 and KB2975719 updates.
Yeah ... FAIL.
Update: Looks like a fix may have been found! Here are the steps posted by Voyager72.
After restoring my pc to the pre-patch state, i was able to install these succesfully by taking the following steps:
1. Reboot into safe mode with command prompt
2. Delete fntcache.dat from c:\windows\system32
3. Reboot back to windows 8.1. The fntcache.dat file is auto-recreated.
4. Install the two famous updates and pray