The August Update for Windows 8.1 (once rumoured to be Update 2) has been pulled from the web and is currently no longer available for download after Microsoft received complaints that it was causing errors and system instability for some users.
If you attempt to visit the original download links you’ll be met with a message stating "The resource you are looking for has been removed, had its name changed, or is temporarily unavailable".
The worst offender appears to be MS14-045 (Vulnerabilities in Kernel-Mode Drivers Could Allow Elevation of Privilege) and Microsoft recommends that users uninstall that particular update. There’s Knowledge Base article covering this at KB2982791 which includes all the known problems and detailed uninstallation instructions.
I haven’t had any problems with the update, have you? Let us know about your experiences in the comments below.