Can't access external harddrive after update

Astrodog

Hi!
I have a problem, yesterday i updated from Snow Leopard to Mountain lion. Ever since i did that i can't access my external hard drive through Finder.
I have a WD Passport, 500 GB.
I can see an icon in finder, but you can't click it at all, its as if it was invisible, or the living life had been dragged out of the poor thing :(
I can't click on it, can't see the files on it, and i can't do nothing with it.

I know the problem is not coming from my external drive, because i have tried the external drive on my friends computers, and it works fine on theirs.
My external hard drive is visible through the WD Smartware software, but i can't drag the files or anything through that software.
I know the problem isn't that the thing is falling asleep, because i have unchecked that box in settings.
I come to you cult members in a time of need, and hope that my noob problem might be solvable.

technochick

What is your friends computer running. That question is important because if they are also on Mountain Lion then the issue is very possibly something in your data. Botched file of some kind.

Have you tried setting up a blank 'test' user to see if it shows up there.

Have you checked if it shows in Disk Utility. Could be something in the formatting of the drive. You might need to see if your friend will let you copy the stuff to his/her computer or to a new drive via his/her computer and then back on yours repartition it etc.