Starting from Service Pack 1, Windows 2008 R2 (… and Windows 7) finally has a built-in tool to reduce the size of the Windows Side-by-Side DLL repository and free up some GBs on system disk. This tool is DISM.exe.
- Install Windows Service Pack 1 then;
- Start and elevated command prompt (run ‘CMD’ as administrator);
- Run the DISM command, which replaces the old VSP1CLN and COMPCLN we used on previous Windows versions: DISM.exe /online /Cleanup-Image /spsuperseded;
- Wait 10 minutes before the task completes ( it ends with “Service Pack Cleanup operation completed. The operation completed successfully”)
Just know that after using DISM you will not be able to uninstall the Service Pack 1 anymore.
Let’s have a look at the used switches for DISM.exe:
- The /online switch tells DISM to work on the running OS installation
- The /spsuperseded option removes the backup files created during installation.
- The DISM log file can be found at C:\Windows\Logs\DISM\dism.log
Optionally you could use the /hidesp option which will remove SP1 (KB976932) from the “Installed Updates” section of Programs and Features, to ensure that users do not try to uninstall the Service Pack.
I hope this helps.