Released: July 2021 Exchange Server Security Updates

We had issues with the EAC working after the July Security Updates on Exchange 2016 CU21 because of the UAC issue. We tried several times to follow the guidance here: https://docs.microsoft.com/en-us/exchange/troubleshoot/client-connectivity/owa-stops-working-after-update to reinstall the update an run the powershell scripts without luck. What ultimately solved our issue was running a command prompt as admin, then running powershell inside that window, and then reinstalling the Security Update in that window while still in powershell. After the reboot both of our Exchange servers EAC was working with no additional powershell scripts or configuration necessary. We had only started the powershell inside the administrator command window to run get-filehash on the update before running it.