Issue: You receive the following error when attempting to install an Exchange 2013 Cumulative Update (CU):
Setup can’t continue with the upgrade because the bbwinsdr (1200), mmc (15404), mmc (15848) has open files. Close the process, and then restart Setup.
For more information, visit: http://technet.microsoft.com/library(EXCHG.150)/ms.exch.setupreadiness.ProcessNeedsToBeClosedOnUpgrade.aspx
Resolution: In order to resolve this error, close all open windows, stop any services related to the processes listed (for example backup software agents). Lastly you may need to close the CU upgrade and reboot the server to close processes (sometimes I’ll set backup process services to manual startup so they don’t launch on reboot).