Microsoft's Enhanced Mitigation Experience Toolkit (EMET), a tool that is designed to "help prevent vulnerabilities in legacy applications (especially line of business and 3rd party apps) from successfully being exploited", has been found to screw up security updates on Adobe and Google products.

The EMET tool was originally released in Sept 2010, and according to MS, it caused any Adobe Reader or Acrobat updates to force unnecessary reboots, plus it stopped Google Chrome auto-updates all together. MS released an update fixing these two issues, and it can be downloaded here.