OWA status code 500 and ECP Could not load file or assembly after installing Security Update For Exchange Server 2016 CU7 (KB4045655) After you installed Security Update For Exchange Server 2016 CU7 (KB4045655) you are no longer able to use OWA or ECP on your Exchange Server 2016. Running the Exchange2016-KB4045655-x64-en.msp installer from an elevated command prompt fixes the issue exchange security update, http error 500, Could not load file or assembly Read More