That’s really bad logic and you’re missing the point here. trusted installer is the owner of the folder. The fact that it’s an old windows drive or that your an admin makes absolutely no difference. It’s a file system ACL, those ACLs don’t just magically disappear from the drive when it’s no longer the system drive.

Take ownership of the folder, add your account or the everyone security group with full access permissions and then delete it.

I’m sorry to say this but the fact that you’re complaining about this is more a reflection on your lack of understanding of how file system ACLs work, in any OS, than anything else.

The braincells were not there to begin with, you didn’t lose them. <= that’s a joke, I’m not trying to be mean.