The upgrade tools for O365 are not silent enough for our needs and so we have been pushing O365 updates using the OfficeC2RClient.exe.
$Proc = Start-Process "C:\Program Files\Common Files\microsoft shared\ClickToRun\OfficeC2RClient.exe" -ArgumentList "/update user updatetoversion=16.0.13801.20294 forceappshutdown=false displaylevel=false" -Wait -PassThru
Initially this was working well. Should office be in use, it would silently schedule an upgrade at the next restart of the computer. However, for the last few runs, it's been showing this error message if users don't reboot soon enough after the exe runs.
We do not want to force computer restarts nor want anything to display for our users. A secondary minor issue is that it shows a "Office was upgraded" summary message if Office is not in use and OfficeC2Rclient.exe can do an immediate upgrade. DisplayLevel=False should mean DisplayLevel=False. Microsoft, why does it continue to show errors and summary boxes to customers despite this parameter?