According to Microsoft's KB article
http://support.microsoft.com/kb/2982791 the following updates can be causing problems:
KB2982791
KB2970228
KB2975719
KB2975331
Here is the list of potential problems:
Known issue 1
After you install this security update, fonts that are installed in a location other than the default fonts directory (%windir%\fonts\) cannot be changed when they are loaded into any active session. Attempts to change, replace, or delete these fonts will be blocked, and a "File in use" message will be presented.
Known issue 2
Microsoft is investigating behavior in which fonts do not render correctly after any of these updates are installed.
Known issue 3
Microsoft is investigating behavior in which
systems may crash with a 0x50 Stop error message (bugcheck) after any of these updates are installed.
Status
Microsoft has removed the download links to these updates while these issues are being investigated.