Viewing Hard Drive From Another Computer - Permissions

Im a computer repair tech, so I'm always hooking up hard drives from other computers to backup data or run certain off-line tasks

With windows 7, I could access the entire contents of a drive without any issues (via external USB dock)

Including documents and settings<user name> (Windows XP drives) or users<user name> (Vista, 7)

But with Windows 8, when I try to view the contents of the users folder, I always get

"You don't currently have permission to access this folder" - Click continue to get permanent access....etc

I never had to do this with Win7.

Now if I hit continue, I can indeed view those files and do my thing...but here's the issue: If Im trying to get a backup of somebody's dying drive, I can't afford the added stress of Windows making permissions change to an entire user folder...nor do I really want to make changes on the files (which the hard drive will be going back into original computer) by adding my credentials to every file/folder in there.

I just want to be able to get the files without any of the permissions prompts, something Windows 7 never asked for.

Is there some sort of setting I can do, registry or whatever....to eliminate this? I have UAC turned off, made some changes in secpol.msc.... so far no luck