Unable to connect galaxy tab pro SM-T520 to PC with windows 8.1 My new PC having windows 8.1 does not recognize Samsung galaxy tab pro connected via USB cable. What to do?
I've tried different cables and different USB ports. It does not appear in Windows device manager. It only pops-out a window saying "The last USB device you have connected to the PC malfunctioned and Windows does not recognize it". I have not installed any drivers for the tab. I need just to copy files from PC to tab (music, movies...).

Thanks for help.
You need to enable USB debugging on the tablet, and then install the USB drivers on Windows. For explicit instructions, see steps 2.1 and 2.2 in the following guide:

How do I install CyanogenMod on the Samsung Galaxy Tab Pro 10.1 Wi-Fi?

Again, you don't have to follow the whole guide to install CyanogenMod, just steps 2.1 and 2.2.