Why can’t I delete old Windows?

Upgrading to a new version of Windows doesn’t automatically remove the old version. This means your PC will keep the Windows installation files for versions you’re no longer using, taking up valuable storage space. There are a few reasons why Windows doesn’t let you easily delete these old installations.

Why Does Windows Keep Old Versions?

Windows keeps old versions on your PC in order to make reverting back to them easier, if needed. Some key reasons Windows hangs onto old versions include:

  • Rollbacks – If a major problem occurs after upgrading Windows versions, you may want to revert to the previous version. Keeping the old files makes this much simpler.
  • Recovery – Old Windows files are used if you need to perform a system restore or recovery to an earlier state.
  • Upgrading Issues – An in-place upgrade from one version to another can sometimes fail or have problems. The old Windows files may be needed to troubleshoot upgrade problems.
  • Driver Compatibility – Downgrading back to an older driver that worked better may require the older Windows version.
  • Application Compatibility – If an app has problems running on a newer Windows version, you may need to revert to the old Windows to keep using the app.

Overall, Microsoft wants to ensure Windows upgrades go smoothly and remain reversible if you run into issues. Deleting old Windows files automatically could make it harder to roll back changes and troubleshoot problems.

How Much Space Do Old Versions Use?

The amount of disk space used by old Windows versions can vary:

  • Windows 7 – Up to 20 GB
  • Windows 8 – Up to 20 GB
  • Windows 8.1 – Up to 15 GB
  • Windows 10 – Up to 20 GB

So if you’ve upgraded from Windows 7 to Windows 10, your PC may be using 40 GB or more just to store the old Windows files! This can really add up over time as you go through multiple upgrades.

Where are the Windows Files Located?

The files for each Windows version are located in the Windows.old folder on your main drive (usually C:).

So for example, you may see folders like:

  • C:\Windows.old\Windows
  • C:\Windows.old\Program Files
  • C:\Windows.old\Users

These contain the system files, program files, and user profiles from your previous Windows versions.

How to Remove Old Windows Versions

If you need to free up drive space or just want to get rid of old Windows versions, here are a few ways to remove the outdated files:

Use Disk Cleanup

Disk Cleanup is a built-in Windows tool that can help delete unneeded files. To use it:

  1. Open Disk Cleanup by searching for it or going to Settings > System > Storage > Free up space now
  2. When Disk Cleanup opens, click Clean up system files
  3. Check the “Previous Windows installation(s)” checkbox
  4. Click Ok and then Delete Files

Disk Cleanup will safely delete the Windows.old folders for any old versions detected on your PC.

Use the Windows Cleanup Tool

Microsoft also releases a separate Windows Cleanup Tool for more advanced file removal. To use it:

  1. Download the Windows Cleanup Tool from Microsoft
  2. Open the tool and check the “Windows Upgrade Log Files” box
  3. Click Clean up

This will delete the Windows.old folders along with any logs and other files related to the upgrades.

Manually Delete the Windows.old Folders

You can also just go into File Explorer, navigate to C:\Windows.old and delete the folders yourself. The key things to remember are:

  • Close all open apps/files before deleting
  • You may need to take ownership of the folders first
  • Be extremely careful and double check what you’re deleting

Deleting core Windows folders manually is riskier, so use the other options if possible.

Use the Command Prompt

For those comfortable with the Command Prompt, you can use these diskpart commands:

list volume
select volume # (where # is the drive with Windows.old)

This will completely wipe the volume and delete Windows.old and all other files. Be very careful when using diskpart like this.

Use Third-Party Cleaners

Programs like CCleaner and Wise Disk Cleaner have dedicated options to find and delete Windows.old folders and other unnecessary system files. Using a third-party cleaner automates the whole process.

Troubleshooting Old Windows Removal

If you have trouble getting rid of those outdated Windows versions, here are some things to check:

  • Close all running programs – Some open files may lock the Windows.old folder.
  • Check the folder permissions – You may need to take ownership to delete protected system files.
  • Boot into Safe Mode – Try deleting in Safe Mode if files are locked while Windows is running.
  • Disable antivirus temporarily – Anti-malware software can sometimes block deletions.
  • Use Administrator Command Prompt – An Admin prompt gives you full control over the PC.

Stuck old Windows versions can be pesky. Applying the right permissions, closing programs, and using Admin tools are key to deleting the folders.

Frequently Asked Questions

Here are answers to some common questions about removing old Windows versions:

Is it safe to delete Windows.old?

Yes, it is perfectly safe to remove Windows.old. The folder only contains your previous Windows installation files that are leftover after an upgrade. Your personal files and current Windows system are not touched.

Can I delete Windows.old manually?

You can delete the Windows.old folder yourself directly in File Explorer. Just be cautious, close all programs first, and ensure you are deleting the correct folder before removal.

Will deleting Windows.old free up space?

Absolutely! Windows.old can take up 15-40GB or more of space depending on your upgrade path. Reclaiming all that storage space can make a big difference, especially on smaller SSD drives.

Can I delete old Windows files without affecting recovery partitions?

Yes, the Windows.old folder is separate from recovery partitions and your main Windows installation. Removing it does not touch your current system or recovery options.

Is it better to use Disk Cleanup vs. deleting Windows.old manually?

Using Windows’ built-in Disk Cleanup tool is the safest option in most cases. It automatically detects and deletes the correct files without the risk of you accidentally deleting something important manually.


Here are some key points to remember:

  • Old Windows versions are kept to facilitate rollbacks, recovery, and troubleshooting.
  • Windows.old can take up a large amount of drive space – 15GB to 40GB.
  • You can use Disk Cleanup or the Windows Cleanup Tool to safely remove Windows.old.
  • Deleting the folder manually works but requires caution.
  • Close open programs, check permissions, and use Admin tools to troubleshoot issues.
  • Removing Windows.old safely reclaims space with no impact on your current Windows system.

Upgrading Windows doesn’t have to mean losing GBs of space to old versions. Use the right tools and techniques to clean out unwanted Windows.old folders and open up valuable storage capacity.