A. Inaccessible data following an upgrade from Windows XP or even from Vista is a common problem. To resolve it, you should take ownership of the files, then grant yourself permissions. You can also perform this solution from the command line by using the Takeown and Icacls command-line utilities. For example:
takeown /f *.* /r
icacls *.* /grant administrators:f /t
These two commands give you full permission on all files and files in subfolders of the current location. Alternatively, you can replace *.* with an actual path.