
This very error is similar to the following error dealt with yesterday “You require permission from trusted installer: How to delete or rename files protected by Trusted Installer” as it protects the Os from illegitimate actions such as unauthorized access and changes to these files. For a similar issue, see how to resolve “Error 740: Elevated permissions are required to run DISM“. Also, see Folder Access Denied, you require permission from SYSTEM: Unable to delete old windows folder.
You may have encountered this error as well, this is absolutely why you are here! When you try to delete or rename some folders in Windows 10, you will get the following error “Folder Access Denied: you require permission from SYSTEM to make changes to this folder.
Reason for Folder Access Denied
There are numerous reasons for this error. In my case, it was due to Folder Ownership rights. In this case, you may need to take ownership of the folder before you can delete it.
Deleting system folders or files can have a dire effect on your system, using this method to delete old Windows file is not recommended. Here are some interesting articles: Taking ownership of a VM: How to fix this error, and how to Restrict Access to USB Drives.
I would suggest using the Windows 10 built-in cleanup tools. But the steps below are ways to take ownership of the folder and grant the needed permission to have it deleted.

How to fix Unable to delete old Windows folder
However, If you are sure you need to delete a folder with access denied and a “you require permission from SYSTEM to make changes to this folder” message, Please follow the steps described below.
Right-click on the folder, Select “Properties” from the context menu. Select the “Security” tab to access the NTFS permissions and Click on “Advanced” button

Change Folder Ownership
In addition, On the “Advanced Security Settings” page. You need to click the change link as shown below in order to change the ownership of the folder.

Nonetheless, Next, you must grant these rights to the Administrator or a specific user account. In my case “Christian”.

Click on Check Names for the object to be identified. Windows will automatically check and complete the full object name as shown below

Furthermore, Kindly refer to this troubleshooting guide for how these errors were resolved. Error Code: 0x80070035: MDT unable to access the Log share, the Network Path was not found, and how to create a hidden share (Administrative share) folder on Windows devices.
Replace ownership on sub-containers and object
Consequently, in this window, you will have to “replace ownership on sub-containers and object” option in the Advanced Security Settings page to take control of the subfolders inside of the folder.
Similarly, Click on the checkbox as shown below.

Nevertheless, Click on Yes on the Windows Security confirmation page as shown below

The changes will be appropriately applied to the user Christian as shown below

Click on Okay as the below is just a suggestion.

Lastly, it is worth pointing out that, taking ownership of a folder.
Replace child object permissions entries with inheritable permissions
You will have to check the “Replace all child object permissions entries with inheritable permissions for this object” option in the Advanced Security Settings page to replace the subfolders permissions with the settings from the parent folder.

The changes will be appropriately applied to the user Christian as shown below

When this step is complete, click on OK. You should be able to delete the folder henceforth.

As you can see, the windows.old folder is no longer present as it has been deleted.

FAQs on Unable to delete old Windows folder
This error occurs because the folder you’re trying to delete is a system folder, and Windows requires special permissions, often held by the SYSTEM account, to modify or delete it.
The SYSTEM account is a privileged built-in account in Windows with full control over system files and folders. It’s used to manage critical operating system components.
It’s safe to delete old Windows folders. Ensure they are not critical to your system’s operation and that you have backed up any critical files.
Yes, you can take ownership of the folder to gain the necessary permissions. This involves adjusting the folder’s security settings in the Properties menu as discussed above.
Be cautious when modifying or deleting system folders. Deleting critical system files or folders can cause system instability or even make your system unbootable. Always back up important data and create a system restore point before making significant changes.
I hope you found this blog post helpful. If you have any questions, please let me know in the comment session.