Delete old windows folder from separate drive

Very typical and frustrating situation. You had your old system installed on typical old mechanical hard drive and you bought shiny,new, expensive and rather small SSD drive. First idea that comes to mind is to install fresh new system on SSD drive and use old one just for not so frequently used but rather big data. Maybe there is a lot of data you want to keep on that old drive and you do not want to format it, you will leave it in system as it is. SSD will hold system and be C partition and old drive will be D partition.

Installation went smoothly and you see there are folders like “Program Files”, “Users” and in particular “Windows” on that old hard drive which you will never ever use again, but they still take up a lot of space. In my case old Windows folder was almost 100 GB big. Deleting all folders except “Windows” goes pretty much without any problems but deleting old Windows installation doesn’t go as easy.

Deleting it from Windows Explorer says you don’t have permissions to delete it. There is no “chmod 777” on Windows to change them. Trying to change permission trough properties dialog also leads to quite strange errors and some ghost non-killable windows.

Total Commander has a bit different approach. It traverses trough directory structure which can take hours and then at the end gracefully fails with same messages as Windows Explorer.

What to do?


Best and easiest thing to do is:

  1. In root of your old hard disks partition next to “Windows” folder make new one named “Windows.old”
  2. CUT    (Ctrl+X) entire old “Windows” folder and paste it into “Windows.old”
  3. Start a Disk Cleanup utility. If everything up to here was done correctly you will see following window.DiscCleanUp_CalculateDiskSpace

    Window should show “Scanning: Previous Windows installation(s).

    This can also take up quite some time to finish. On my machine it took more then 3 hours

  4. After scanning process is done select “Previous Windows installation(s) and click OK. PreviousWindowsInstallation
  5. When confirmation dialog pops up click on “Delete Files” AreYouSureYouWantToDeleteWindows 
  6. Done!
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About me

Bizic Bojan is Co-Founder of Amida IT-Services GmbH and Software Architect with focus on .NET, C++, Python and Cloud Native solutions. 



The opinions expressed herein are my own personal opinions and do not represent my employer’s view in any way.

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