Please follow steps below for troubleshooting：
- Make sure the appearance of the USB device and USB port are intact
- Make sure tablet operating system supported your USB device function
- The USB device which large of power consuming (mass capacity external HDD), please use the external power supply to make sure the power is enough to work
- Cross test with another tablet or computer
- Access Safe Mode by long pressing power key > tapping and holding Power Off > tapping OK
If your tablet works well in Safe Mode, there may be some 3rd apps that cause malfunction
Please reboot your tablet and check again if it works well
- Backup your data and perform factory data reset
