OWA status code 500 and ECP Could not load file or assembly after installing Security Update For Exchange Server 2016 CU7 (KB4045655) The ‘reason’ that this happened is that the security patch was not completely installed because it was not ran from an elevated command prompt and here is how you do that Start an elevated command prompt Type Exchange2016-KB4045655-x64-en.msp and let it run. It will take ... exchange security update, http error 500, Could not load file or assembly Read More