device: Samsung Tab 10.1 GT-P7510
computer operating system: Windows 8.1
The Problem
Upon upgrading the ROM on a Samsung Tab 10.1 GT-P7510, no matter how many times I unplugged and plugged in the Tablet it wouldn’t show up on My Computer. This is a problem when one is trying to transfer files between a computer and the tablet.
The Solution
Don’t worry, there’s no software upgrade or major modification needed. Simply go to:
Settings->Device Storage->click the three dots in the top right corner->USB Connection->Enable Media Device (MTP).
If you plug your Samsung Tab 10.1 back into your Windows computer you should be able to see it again as it pops up and allows you to browse to the folder within My Computer.
Hope this helps!
Source: Stackoverflow