Since Patch Tuesday this past week, Microsoft has been receiving reports of severe system errors caused by one or more of the updates. In response, the company has pulled several updates from download channels and offered advice on how to remove them. In one case, it recommends that users uninstall the update.
Updated on August 16: A Microsoft spokesperson tells ZDNet "[w]e are aware of some issues related to the recent updates and we are working on a fix."
Edward Langley at the Naked PowerShell Blog has written a series of PowerShell scripts to determine if any of the relevant updates are installed on a system.
The most severe case appears to be MS14-045 (Vulnerabilities in Kernel-Mode Drivers Could Allow Elevation of Privilege). The security advisory recommends that users uninstall that update.
Microsoft reports problems with three other updates and has pulled them from download and provided uninstallation instructions, but has not specifically recommended that users uninstall. Two of these are non-security updates released on Tuesday. The third is a re-release ("Revision: 7.0") on Thursday, August 14 of an older update rollup for Windows RT 8.1, Windows 8.1, and Windows Server 2012 R2; only metadata was supposed to change in the new version and users who had previously installed it did not need to reinstall.
A Knowledge Base article written for these problems (KB2982791) includes uninstallation instructions and lists three known issues. We list #3 first because it is the most severe:
The uninstallation instructions are long and involved and are detailed in the Knowledge Base articles linked to above.