Microsoft's Patch Tuesday in the last month has caused problems, especially for Outlook users. It seems this latest update has done that, too.
Microsoft's Patch Tuesday update KB 3114409, intended to help admins keep Outlook 2010 from starting in safe mode, has in fact done the opposite. Many Outlook 2010 customers report that installing KB 3114409 forces Outlook to start in safe mode. Microsoft, Once Again, Has a Problem With Patch Tuesday [infoworld.com]
Microsoft has pulled the patch causing the problems.
How odd. You would have thought that Microsoft would have learnt from the previous patch.
I'm not affected by that particular problem, but I have noticed that the performance of one of my Win 8.1 PCs has noticeably slowed since the latest update.