I have had this issue with EVERY upgrade that I have ever attempted for Exchange Server from 2013 through 2019 CU5. You go to run the setup program and during the prerequisite checks, setup stops. The error listed is:
A restart from a previous installation is pending. Please restart the system and rerun setup.
During the prerequisite checks, Exchange Setup looks in the registry at the following keys:
- HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\PendingFileRenameOperations
Nine times out of ten, a restart does NOT remediate this error. In order for setup to continue properly, you must do the following:
- Open regedit: Start > Run > regedit.exe
- Set the HKLM\SOFTWARE\Microsoft\Updates\UpdateExeVolatile key value to 0 or delete it if present. <– This one is usually NOT present.
- Delete the HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\PendingFileRenameOperations key.
- Re-run Setup.
You should now be able to run setup and upgrade your Exchange Server.