What tablet are you using?
Depends on how its connecting as a device/mode. USB/MTP/PTP
USB being the standard or older/common version of connection used by flash drives, storage sticks, etc.
MTP being the newer standard of connection ( Media Transfer )
PTP also a newer standard commonly prompted w/ media transfer for camera files on computers that don't support MTP mode.
Otherwise if non of the above applies you may want to check with your device's OEM website and make sure you have the newest/proper driver installed in your computer to support it properly.