Windows 10 Update Wastes 20GB: How to Get It Back

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This month, Microsoft started rolling out its Windows 10 Anniversary Update, a major upgrade to the company's flagship operating system. The update adds several features, including Windows Ink, Cortana Phone Sync and Windows Hello logins for applications, but it also consumes about 20GB in space on your storage drive during the installation process.  

windows old

If you recently installed the Anniversary Update, you may notice that your storage drive has 20 to 22GB less space than it did before. The problem isn't with the update itself, but with the old software it leaves behind. Every time you perform a major update -- not a patch, but an actual change to the OS build number --  Windows keeps a backup copy of the old version in a folder called Windows.old on your C drive. Since Windows 10 takes up about 20GB, the backup folder eats up all that space. Upgrading from Windows 7 or 8 to Windows 10 also creates this backup folder.

The reason Windows 10 keeps a backup is to help you roll back to the previous build number in the event that you have a serious problem. In fact, in the case of Anniversary Update, a small number of users who have both SSDs and hard drives, with programs stored on the hard drive, have experienced freezing problems. After 10 days, the Windows.old folder may delete itself -- or it may not.

Unless you have a serious freezing problem, which you would notice right after the upgrade, we recommend that you delete the Windows.old folder to save a lot of space. The OS won't let you just highlight the folder and hit the delete key, though. Here's how to delete the Windows.old folder:

1. Launch Disk Cleanup.  You can get there by searching for "Disk Cleanup" in the Cortana box.

disk cleanup

2. Select the C drive and Click Ok.

Click Ok

3. Click Clean up system files.

Clean up system files

4. Select the C drive again and click Ok.

Click Ok

5. Select Previous Windows Installations and hit Ok. You may also want to select all the other items on this list.

select previous windows installations

6. Click Delete Files.

Delete Files

7. Click Yes if prompted to confirm.

Click Yes

You'll have to wait a few minutes for the files to delete, but your C drive will have a lot more space afterwards.

Windows 10 Annoyances and Problems

Author Bio
Avram Piltch
Avram Piltch, LAPTOP Online Editorial Director
The official Geeks Geek, as his weekly column is titled, Avram Piltch has guided the editorial and production of since 2007. With his technical knowledge and passion for testing, Avram programmed several of LAPTOP's real-world benchmarks, including the LAPTOP Battery Test. He holds a master’s degree in English from NYU.
Avram Piltch, LAPTOP Online Editorial Director on
Add a comment
  • Halfan Kibamba Says:

    updates my previous storage file adroids

  • EricD Says:

    We have a pc we have upgraded to win 10, followed your instructions and when I get to the part where the option to delete previous installations is supposed to be, there is no such option. However i know that windows has been saving the old installations as my windows folder is over 22gb. We are running a 32gb emmc so I need that space, does anyone know what to do when disk cleanup doesn't give the above option?

  • Debra Says:

    Thank you thank you thank you! I have a 128gb Surface 3 that went down to 79gb free after the update. this was a replacement tablet for a Surface 3 that already had Anniversary but the net ip tcp/ip kept getting corrupted. wasnt expecting such a big loss since the old s3 had plenty of space.

  • Robert Says:

    For what it's worth, Win10 will prompt you about a week later to delete your old backup and install. They obviously recognized that the upgrade took up a lot of disk space and wanted to help with that but I also realized people would probably want to run the update for a week or so to insure everything is working well.

    You just might need to give MS props on this one, as it worked great for me. When I was prompted a week later I just hit "yes" and it happily went removing all the old stuff while I continued to work.

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