Just some guesses and assuming that the PC / tablet connection is USB.
- The PC platform recognizes the USB mass storage connection
- The PC platform does not recognize the USB storage protocol.
The USB protocols are:
-MTP (Media Transport Protocol) not recognized by Linux without enhancement
-MSD (Mass Storage Device) not recognized by Windows without enhancement
Don't know where Mac's fall in this, but it has caused me some headaches with my Coby MID7042. Android 4,x does not support MSD and has switched to MTP. Prior releases support MSD only.