By default, Windows 10 gives you ten days to roll back major upgrades like the October 2018 Update or April 2018 Update, which are released every six months. But you can extend this ten-day window and give yourself more time.

This only works right after you’ve upgraded, when you’re in the ten-day period before Windows removes the files. You can’t increase the amount of time before you upgrade—only after.

How This Works

The upgrade process, which happens once every six months, is just like upgrading to a new version of Windows. When you upgrade, Windows 10 save your old operating system files in a Windows.old folder. You can roll back to the previous version of Windows 10 if you encounter a problem, and Windows will restore the files from the Windows.old folder.

However, Windows only gives you ten days to make this decision. After ten days, Windows deletes those old files to free up disk space. This is a change from the initial versions of Windows 10, which gave you 30 days to decide.

You can increase the number of days you have to restore the old version if you like. This gives you a more extended amount of time to make your decision. For example, you could increase the uninstall window from 10 days to 30 days, and you’d be able to roll back if you ran into a problem around day 20.

This won’t give you additional time to roll back an upgrade if Windows has already deleted the files. This trick just makes Windows wait longer before deleting the files.

These files will use space on your system drive for longer if you extend the window. However, that’s the only downside. You can still remove these files to free up space any time you like. If you’re not hurting for space, there’s no downside to doing this—you’re just giving yourself more flexibility.

How to Increase Your Uninstall Window

First, you must open either a Command Prompt or PowerShell window. Whichever you launch, you must open it with Administrator permissions.

To quickly open a command line as Administrator, right-click your Start button and select “Windows PowerShell (Admin).”

Run the following command to see how many days you have to roll back:

DISM /Online /Get-OSUninstallWindow

You’ll see “10” if you haven’t changed anything yet, which means you have ten days to roll back before Windows deletes the files.

Note: If you see “Error 1168” with the message “Element not found” while running any of these commands, this indicates that you don’t have operating system rollback files on your computer. You can only run these commands while the OS uninstall files are on your PC. You’ll have to wait until just after your Windows PC has performed a major upgrade before running these commands.

To increase the number of days, you have to roll back an upgrade, run the following command, replacing # with the number of days you want to use:

DISM /Online /Set-OSUninstallWindow /Value:#

For example, to increase the uninstall window from the default ten days to 30 days (the maximum), run the following command:

DISM /Online /Set-OSUninstallWindow /Value:30

How to Roll Back an Update

To uninstall a Windows 10 upgrade, just head to Settings > Update & Security > Recovery. If any previous operating system version files are available, you’ll see a “Go back to the previous version of Windows 10” option. Click the “Get Started” button to start the rollback.

You can also initiate an uninstall from DISM if you prefer. Just run the following command:

DISM /Online /Initiate-OSUninstall0

RELATED: How to Roll Back Builds and Uninstall Updates on Windows 10

How to Delete the Previous Windows Installation Files

You can delete these files at any point in time to free up space, even if you just upgraded earlier today. You won’t be able to roll back after deleting the files.

To remove the old Windows files, head to Settings > System > Storage > Free Up Space Now. Ensure “Previous Windows Installation(s)” is checked and click the “Remove Files” button.

This same option is also available in the old Disk Cleanup utility.

You can also remove these files from the command line if you want. To do so, run the following command:

DISM /Online /Remove-OSUninstall

RELATED: Use Windows 10’s New “Free Up Space” Tool to Clean Up Your Hard Drive

What About Smaller Windows Updates?

The rollback process is different from uninstalling smaller Windows updates. You have as much time to uninstall smaller Windows updates as you like. However, when Windows 10 upgrades to a new major release, you can no longer uninstall those smaller updates—they’re just part of the new base version of Windows 10.

RELATED: How to Roll Back or Uninstall a Problematic Windows Update

If Windows has removed the downgrade files and you want to roll back to the previous Windows 10 system, there’s no way to do so. All you can do is reinstall Windows 10 on your PC using older installation media.