Microsoft released the Fall Creators Update for Windows 10 this week. Windows keeps a copy of the old operating system ready after feature updates, mainly to make it easier to roll back the update if issues are encountered.

While that is mighty helpful in that case, it means that the old installation of Windows occupies twenty, thirty or more Gigabytes of disk space.

A quick check on my Surface Pro 4 revealed that it used 106 Gigabytes of space. While that is certainly an error in the calculation, as the Surface's hard drive has a size of 116 Gigabytes, it still means that you will be able to free up quite a bit of disk space when you do so.

Word of advise: It is recommended to remove the old installation files only if you are confident that you don't need to roll back to the previous version. If you are in doubt, create a backup of the main Windows partition so that you may restore it should the need arise to roll back the Windows version.

Do the following to check how much disk space you can free up.

1.Tap on the Windows-key, type disk cleanup, hold down the Shift-key and the Ctrl-key, and select the entry. This loads the elevated interface right away. Check out Speed up Disk Cleanup System Files loading for additional details on this.
2.The entry that you are looking for is called "Previous Windows installations". You can check other entries to free up even more disk space.
3.Hit the ok button once you have checked all entries to commence with the deletion of the files.
4.Confirm the "are you sure you want to permanently delete these files" prompt.

Windows deletes the files and frees up the disk space in the process.

The Windows 10 Fall Creators Update comes with an automatic clean up option that you may enable as well.

1.Use Windows-I to open the Settings application.
2.Navigate to System > Storage.
3.Toggle the Storage sense option to on.
4.Select "change how we free up space".
5.Check "delete previous versions of Windows".
6.Close the Settings application.

Windows 10 will delete previous versions of Windows 10 ten days after installation of the update. This gives you more than a week to determine whether the new version is stable and functional before the old version gets deleted.

The main advantage of this method is that it is automated. Set it once, and you never have to worry about cleaning up disk space manually again. The downside is that the previous installation files are deleted after exactly ten days. This means that you only have ten days to test the new version, and also that disk space won't be freed up earlier.

@jimmy7, can you move this to tutorials?

Originally Posted by MusicX

@jimmy7, can you move this to tutorials?

Yeah, you're right. Moved!