If your micro:bit appears to have developed a fault, this article works through some potential problems and provides steps to try to bring the device back to life.

Test on USB

Plug the micro:bit into your computer with a *USB lead capable of transferring power and data. It should appear as a MICROBIT drive and the yellow system LED on the back should light up.


On computers running Windows, MICROBIT appears as a drive under Devices and drives.   

On a Mac it appears as a new drive under Devices.

* Some USB leads are 'power only' leads (especially poor quality leads or those designed to charge mobile phones). You will need to use a USB lead that transfers data for example a lead used for smartphones or a digital cameras.

If the yellow LED does not light up, it is likely that either your USB lead has developed a fault, or your computer might have powered down the USB port. This can happen if you short out your micro:bit when running from USB and plugging in electronic components. Some Mac's (when they power down their USB port) require a restart for the USB port to recover, in this case, please try:

  • another lead
  • another USB port on your computer 
  • restarting your computer 

Also, try your micro:bit in a different computer, just in case your computer has powered down its USB ports for some reason.

Older computers can take a few seconds for the MICROBIT drive to register when you first plug the micro:bit into a new USB port, so wait for about 20 seconds to see if it appears in your file manager. If it does not appear, then press the reset button on the back and wait another 20 seconds.

Antivirus and Device Management software

Ensure that any antivirus software or school device management policies you are using exclude the MICROBIT drive from being scanned automatically. Automatic scanning can prevent the micro:bit from mounting as a drive. For more information please read Why doesn't my computer detect the micro:bit?

MBED Driver (Windows)

If you have upgraded from a previous version of Windows to Windows 10 or already have the MBED driver installed, Windows may not detect the micro:bit. In this case, you will need to remove the old driver to allow Windows to automatically install it.

Hardware Faults

If you see the yellow system LED lit but no MICROBIT drive after the tests above, it is possible that your micro:bit has developed a fault. You should contact the supplier that you purchased your micro:bit from and ask them about their returns process. 

However, if you can now see the MICROBIT drive on your computer, test it with our smile test program by flashing the .hex file to your MICROBIT drive. Wait for the yellow LED on the back to stop flashing and you should get a smiley face on your micro:bit. 

Motion Sensor

If you find your compass or accelerometer isn’t working the way you expect it to, it may be a result of recent software updated to support the micro:bit motion sensor revision. Modifications have been made to the underlying software that supports the compass and accelerometer, so you may need to update your hex file.

If you're still having compass troubles, check out our tips for calibration.


If you have been using your micro:bit with Bluetooth and flashing programs over the Bluetooth from your phone or tablet, there is a chance that you might have interrupted the code transfer process while this was happening. 

Our article micro:bit shows `+` symbol or is unresponsive after flashing with Bluetooth explains how to reset your micro:bit if the code transfer isn't working.

Bluetooth pairing mode will not work if the micro:bit has previously been flashed with a MicroPython hex file. In this case reinstate Bluetooth by flashing a MakeCode program.

Maintenance Mode

If you were accidentally holding the reset button at the back at the time you copied the program onto the micro:bit, this would have put the micro:bit into maintenance mode. As a result, a new MAINTENANCE drive will appear in your file manager. If the reset button is pressed while powering up the micro:bit (even after you loaded the .hex file), the micro:bit will go into maintenance mode and will not accept your user code. 

To resolve this issue, power down the micro:bit and reconnect the power source, being sure not to press the reset button at the back as you are doing this. The MICROBIT drive should re-appear.

If you are still experiencing issues, please try upgrading the firmware

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