Try wiping the system cache partition, which contains temporary system log files and other data that isn't harmful to clear:
1. Reboot your tablet into the bootloader by turning it off, and then pushing the volume down, volume up, & power buttons at the same time.
2. Then, use your volume buttons to select Recovery.
3. If you?re on a stock recovery, wait until you see the Android with the red exclamation point, and press volume up + power at the same time. When you release the buttons, the Recover Menu should appear.
4. Using the volume buttons, select the option to clear your tablet?s cache, and press Power to execute.
5. When the cache wipe is done, press Power to reboot.