Problem: Exchange Server 2016 CU12 upgrade failedError: Could not find a part of the path, ‘C:\Windows\Temp\ExchangeSetup\bin\EnterpriseServiceEndpointsConfig.xml’.
Solutions:To fix this issue: following the following steps.
Open the registry editor and go the following location.
Under “v15” folder check if the following outlined keys are available and they have the following string “ConfiguredVersion, UnpackedVersion, and PostSetupVersion” with matching the same version values.
After string update in all the Role keys the issue was resolved, and we were able to update the CU12.
Note: If you are running this issue on a different version, all the keys with the server "Roles" should be fixed.