Botched Update For Microsoft Outlook 2010
Many of our customers are reporting that installing KB3114409 will force Outlook to start in safe mode. The patch has been removed from windows updates, but anyone who has it installed should remove it immediately and then Outlook will start working normally again.
It took Microsoft around 12 hours to pull the faulty patch.
Just last month, another update known as KB 3097877, caused Outlook to freeze, and blocked users from logging.Microsoft rereleased this patch using the same KB number as the original botched patch rather than using a new patch number.