Error: he following error was generated when “Serror.Clear(); $dlIFile =join-path $RolelnstallPath “bin ExSMIME.dII”; $regsvr =join-path (join-path $env:SystemRoot system32) regsvr32.exe; start-SetupProcess -Name:”$regsvr” -Args:”/s -Timeout:120000; “was run: “Microsoft.Exchange.Configuration.Tasks.TaskException: Process execution failed with exit code 3. at Microsoft.Exchange.Management.Tasks.RunProcessBase.InternalProcessRecordo at Microsoft.Exchange.Configuration.Tasks.Task.

Microsoft.Exchange.Configuration.Tasks.Task.InvokeRet ableFunc(Strin • funcName, Action func, Boolean terminatePipelinelfFailed)”

Fix

Checking logs there was missing Visual C++ 2012 and 2013 runtime. 2013 was a new requirement for CU18/19 so no surprises there, but 2012 has been a req for as far back as I can see. Definitely wasn’t present. So the pre-flight dependency check script doesn’t actually check for deps… From what I can tell it checks for the presence of RSAT and that’s about it. Once that was sorted (I had to install both 2012 & 2013) I was able to run CU19 again successfully.