KB2918614 – Not only does it break MSI Repair .

“What the security bulletin doesn’t say is that the change in Windows Installer repair operations means that application repair attempts will be met with a User Account Control credential window each time. However, the credentials required are administrator access.”
Bug or Feature? KB2918614 Alters Windows Installer Behavior

KB2918614 Should your application install use Active Setup, to say, personal per-user settings, then this MS14-049 security patch causes a UAC prompt as well.

The current workaround, courtesy of happysccm,  is as follows:

  1. Uninstall the application and reinstall it with the security update installed. (sourcehash file generated with security update)
  2. Manually copy the sourcehash file to c:\windows\installer folder. As the sourcehash file is generated based on the application files, the sourcehash file generated on computer A can be used on computer B.

Not scalable if, say, you have 500 packaged applications deployed to customers.