Permissions error opening from external hard drive

I backed up my unity project on an external hard drive so I could reformat my laptop to Windows 7. I'm trying to open up the files and copy them on to my laptop but I keep getting an error saying "You require permission from S-1-5-21-1886576845-417619904-831270952-1007 to make changes to this file". This is after it asks for administrator permission which it accepts just fine.

Is this an error with some administrative options from having reformatted or something else, and what can I do about it?