Windows 10: Account Unknown Under File Permissions / also TrustedInstaller

For anyone who gets stuck with not being able to Delete a Folder or File due to an oddball User such as S-1-5 etc, or even TrustedInstaller, here is the process to follow. You will typically come across it when you see a User called S-1-5- xxxx etc. or something similar to that. This tutorial also applies to TrustedInstaller if that user is preventing you from deleting a Folder. These S-1-5 xxx type users are usually left over from a partition clone, folder copy from another system etc. Basically all you need to do is take Ownership of the Folder/File. Then you can delete that oddball user

:)

 

TrustedInstaller permissions

It's because you are are just typing 'TrustedInstaller'. That works to find the common user, group or security principle names, such as your user name or SYSTEM, but for TrustedInstaller you'll only be able to find it when you click 'Check Names' it if you type its full name: NT Service\TrustedInstaller

Edit: but I see you have already found and used that *Wink

 

Account Unknown Under File Permissions

Recently, in troubleshooting another issue, the support tech created a new local admin user "TEST" on my machine. I don't believe any file permissions were manually assigned.



That did not address the problem, and they deleted the user.



When I go to a file or directory and do Properties, Security, I see "Account Unknown(S....)".



I try to remove that and get:



You can't remove Account Unknown(S.....) because this object is inheriting permissions from its parent. To remove Account Unknown you must prevent this object from inheriting permissions. Turn off the option for inheriting permissions, and they try removing Account Unknown again.

If I turn off inheritance, what problems might that cause in the future? Or do I then turn it back on later?

I've seen some articles about this, but am afraid I'm going to keep digging a deeper hole by trying things and decided to put down the shovel and ask for more expert advice.

Thank you in advance.

Thank you,

Scott

 

Account Unknown has full Security permissions on my own User - huh?

Hello glnz,

You will see "Account Unknown" for an account that is not currently available. This could be from an account you deleted that had permissions, or from an account on another computer that is not connected.

Either way, it's safe to remove any listed "Account Unknown" entries in permissions if you are sure it's for an account that will no longer need permissions for the item.