Starting with Windows Vista, the Windows.old folder is created when you upgrade to the latest version of Windows. It has all the data and files from the last version of your Windows, as said above.

This folder is actually helpful because in a case where you don’t really like the new and upgraded version of your Windows OS, you can simply restore the system of the old version. You could also find some files or folders in Windows.old folder if they aren’t copied to the new installation of Windows OS.

So, basically, this folder contains all the files and data of your previous Windows OS version. From the installed programs to the Windows system files, and to each user’s files and account settings – you will see it in there.

The new Windows OS version that you’ve installed will just keep it on your computer so that if you wish to go back to the old version or you’ve missed copying some of the important files, you can access it easily. The new version will automatically delete it after 30 days.


Restore Important Files From Windows.old

When you upgrade your Windows 7 or Windows 8.1 to Windows 10, some important files won’t be saved in the operating system of the new Windows OS, which sounds like a nightmare, especially if these files are private and personal. But, you don’t have to worry, you can still retrieve these files by using the Windows.old folder. However, you only have 30 days to retrieve it.

If important data or files aren’t saved on the new Windows OS, you can still recover it using the Windows.old folder because all files and data from the previous version are inside it. Here’s how.

 1. To recover files, all you have to do is open the File Explorer window.

 2. Go to C:\Windows.old to access the Windows.old folder.

 3. The files and data of the previous operating system will appear. Browse it and look for the files that you want to restore.

 4. If it’s for personal file, go to C:\Windows.old\Users\your_name.


Deleting Windows. old folder

When your Windows OS becomes upgraded, the system will create a folder that has all the folders and files from your previous Windows OS version. This will be done automatically by your system and will be named as Windows.old.

If your computer performs poorly after updating to the new Windows OS, then it might be because of the Windows.old folder. It can eat up a lot of space on your computer so you should delete it immediately once you’re done restoring all the important files from it. But, how? Here’s a step by step guide that you can follow.

1. Go to the search bar of Windows. It is an icon shaped like a magnifying glass, located at your taskbar’s left side.

 2. In the search bar, type Cleanup.

 3. A list of search results will appear. Click on the Disk Cleanup in the search results to launch it.

 4. Once done, select the button that says “Cleanup system files”.

 5. Select the (C:) drive if it happens that you have multiple drives on your computer. But if you only have one, it will just be that drive.

 6. A drop-down with a list of files to delete will appear. Select the “Previous Windows Installations” option in the drop-down.

 7. To confirm and proceed with the deletion, just click OK.


Downgrading Windows 10

If you wish to downgrade and go back to the old version of your Windows OS, you can also do it, too. Downgrading or going back to the previous Windows version of your computer is easy. Here’s how.

 1. Just go to Settings and look for the Update & Security option.

 2. Click the Update & Security option and go to Recovery.

 3. Depending on what old Windows version is installed on your computer, a “Get Started” button will appear under the “Go back to Windows 8.1” or “Go back to Windows 7” option.

 4. Click the “Get Started” button to restore the operating system of your previous Windows version with the use of Windows.old folder.

Important Note: As said earlier, this folder will be deleted automatically by the new system after 30 days so you have to decide whether you will stick to the new upgrade or go back to the old version.