Data Recovery on non-rooted Samsung Galaxy Tab 10.1v
This might or might not work. Insert an SD Card, preferably more than 4GB.

Boot into android stock recovery.

Power + Home + Vol. Up


Scroll down to backup internal data. 

Remove the SD card.

Go through the steps of unlocking the boot loader but don't flash a custom recovery yet.

Reboot into recovery(stock) after unlocking the boot loader. Restore user data.

Flash a custom recovery. Root your device. Then go about what you we're trying to do.