Office Online (WACSM) service cannot be started
Symptoms The Office Online service (WACSM) fails to start from the Services console and PowerShell with this error: The Office Online service on Local Computer started and then stopped. Some service stop sutomatially if they are not in use by other service or programs. In the Windows Application event logs and as well as sometimes in the Trellix event logs, the following error appears: ExP:DEP Stack Blocked an attempt to exploit C:\WINDOWS\SYSTEM32\INETSRV\W3WP.EXE In addition, the Windows Application event logs show: Service cannot be started. System.InvalidOperationException: The certificate has not been specified . Even with the Office Online service not running in any of the farm members, OOS still renders Office documents, which is strange. As expected, however, it won’t let you run any Office Online PowerShell commands (e.g. Get-OfficeWebAppsFarm). Causes Case 1 : A certificate with the same Subject name is found in the Personal Ce...