Take Full Control of Windows 10 Files

When you install a new hard drive into a computer with Windows 10, and remove the old hard drive, it still has Windows folders on it.  If you install that drive as a second drive, you can safely remove those files because they’re not part of the operating system any longer.  Unfortunately, Microsoft’s file security is a bit fiddly, so that even when you take ownership and full control of the files, they still might block you from deleting them.

This is the file management equivalent of Demi Moore’s character in A Few Good Men saying, “I strenuously object.”

I don’t spend too much time trying to fiddle with operation system files.  I realize there’s cruft in there but you can use some operating system tools to remove most of it.  There’s Disk Cleanup (hit your Windows key and type that) and Windows 10 has introduced Storage Sense.

Microsoft Windows 10 Storage Sense will auto manage temp files and deleted files to help keep free space on your hard drives.

That’s all well and good when you’re on the primary hard drive (usually C:) of your computer.  But what if your C: drive is now your D: drive?

Wipe Out

The easiest thing is to just wipe the disk clean and start fresh.  I’m not talking data wiping for privacy purposes.  But each drive has a number of layers that allow the operating system to interact with it.  If you wipe out those layers – the volume, the partition – then it can’t interact with the drive any longer.  The fastest way is to delete the existing partitions, which will delete all the data on them, and create a new partition and format it.

You can type diskmgmt.msc to open up the native Windows 10 disk manager.  It’s handy to know that exists.  You can right click on any disk, select delete volume, and it will.  And that’s why I tend to not use the Windows 10 disk manager.

Right click on a drive to delete your volume

It happens immediately.  So if you right-click on C: instead of F:, then you have an unrecoverable Windows computer, because your files and operating system will disappear.  If you really want to mess with partitions, I would use Mini Tool’s free Partition Wizard.  It does the same things as Disk Manager but you have to apply each step after you’ve told it what to do.  It means you have 2 chances to not mess up.

Frankly, I don’t like playing with partitions any more than I like reinstalling operating systems.  Also, I had other files and folders on this disk that I didn’t want to delete and couldn’t move to the new hard drive.

Take Control

This is actually pretty straight forward when you know how.  But if you’ve ever tried to delete anything and been told that

You require permission from TrustedInstaller to make changes to this file

then you may not be sure why TrustedInstaller can tell you what to do.  Since the owner of the Windows folder – and the cruft that Windows 10 installs in the Program Files folder – is a system function, it blocks you from changing those files.

Which is good, when they’re used for the operating system.  But it’s needless when those files are redundant, sitting on a second drive.

The process to take full control of those files takes three steps.

1.  Take ownership of the files.  First, make sure you’re working on the old drive, not the one you just installed that has your actual operating system on it.  I opened File Explorer and gave the old drive a new name (right click and select Rename) to help me make sure I was on the right drive.  Make sure it applies the ownership change to all objects in subfolders.  Once you have changed, at the top, to the person who you want to own the file, a checkbox will appear below the new owner’s name.

Be sure to check the box to replace owner on subcontainers and objects

Once you click the Apply button, it will make the changes.  It will take quite a while – like 15 to 20 minutes – but you shouldn’t get any error messages.  You will, however, get a warning at the end that you need to exit the file properties before it shows that you have ownership.  So click the OK button, and then click OK on your folder properties window so that you return to your File Explorer window showing the old Windows folder.

2. Make all the files readable.  Right-click on the Windows folder again, and this time the very first thing you’ll see is that you can toggle on and off the ability to read a file.  If a file is read-only, it means you can look at it but can’t change it.  If it’s read-write – which means that the box next to Read-only is unchecked, you can make changes to the files.  Now that you are the owner of all of these files, you can make them read-writeable.

Owners can change the read-only status of files.

It will prompt you to apply to all subfolders.  Do that.  You want to make all of the subfolders and subfiles writeable (deletable) in the same way you took ownership of all of them.  This will take just as long as the last step.

3.  Take Full Control.  This one stumped me.  Once you have ownership of the files, you should be able to take full control of them.  Right click on the Windows folder again and this time return to the Security tab.  Choose Advanced button just like you did on step 1.  This time, though, you’re already the owner.  Select the group in which your owner is – in my case, it was Administrators (MYPC\Administrators).  There were 2 listed.  I chose the one that has Full Control, but I don’t think it matters.  The reason there are 2 is that you don’t actually have full control of everything.

Click the Change Permissions button.  You’ll now see a list, with Special Permissions unchecked.  If you chose the Administrators group that has Full Control, everything else will be checked.  Special Permissions is not only unchecked, but greyed out so it can’t be checked.  Click the link that says Show advanced permissions.  You’ll see a bunch of new permissions now.  Click Full Control again, so that all of the check boxes are marked.  Now click OK and it will apply the new security to all of the underlying files.   It takes about the same time, again, as the other two steps.

Now you should have really, truly full control of the files.  Right click on the Windows folder and click Delete and it should remove the files just as if they were any other file you’d created.  I regained about 20 GB once it was all over.




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David Whelan
I improve information access and lead information teams. My books on finding information and managing it and practicing law using cloud computing reflect my interest in information management, technology, law practice, and legal research. I've been a library director in Canada and the US, as well as directing the American Bar Association's Legal Technology Resource Center. I speak and write frequently on information, technology, law library, and law practice issues.