ok i just had this problem with no solution in sight so i just started messing around with the settings and i got it working! so say you dad spilled water on his laptop but theres important files on the hdd. and say the laptop had windows xp with a master account that had a password. now say you go out and buy an external hdd enclosure and place it in there. when you try to access the master account it says you dont have permission. here are steps to get rid of it. the computer i was working with to fix this had vista on it
go into my computers
right click on the external hdd
go to properties
go to security tab
under 'grounds or user names' click on Everyone
click edit
click everyone and then go down and highlight all ALLOWS
click OK
go to advanced
click owner tab
click edit
click administrators (YOURNAME-PC\Administrators)
click 'replace owner on subunits and objects'
click OK
should take about 5-10 minutes for it to process then remove external hdd and plug it back in and it should work
