How To Get Windows 8.1 To Recognise USB Mass Storage On Your Phone
I have had the problem for ages that when I connected my Samsung Galaxy GT-S5360 into my Windows 8.1 PC nothing happened - Windows 8.1 simply refused to recognise the device - not even anything in device manager - nothing - nada
However it would recognise the phone if I set the phone to download mode - but I want to use my phone as mass storage
Well after months of trying I finally found a really stupid solution
Solution
Install the usb drivers for your phone as normal
connect the phone to pc via usb cable (nothing happens other then a few beeps as normal)
now plug in any usb dongle that you have already installed on your pc - like a usb wireless mouse dongle
suddenly windows detects the phone and you can now set your phone to mass storage from the phone status bar
Every time you want to connect your phone in mass storage just plug it in then plug in the other usb dongle after