HEEELPZZZ

Problems I've encountered

I messed up something and my board could not be detected by the usb port
Text and solved by https://learn.adafruit.com/adafruit-metro-m0-express/metro-m0-help

Ack! I "did something" and now when I plug in the Metro, it doesn't show up as a device anymore so I cant upload to it or fix it...
No problem! You can 'repair' a bad code upload easily. Note that this can happen if you set a watchdog timer or sleep mode that stops USB, or any sketch that 'crashes' your Metro

- Turn on verbose upload in the Arduino IDE preferences
- Plug in Metro M0, it won't show up as a COM/serial port that's ok
- Open up the Blink example (Examples->Basics->Blink)
- Select the correct board in the Tools menu, e.g. Metro M0 (check your board to make sure you have the right one selected!)
- Compile it (make sure that works)
- Click Upload to attempt to upload the code
- The IDE will print out a bunch of COM Ports as it tries to upload. During this time, double-click the reset button, you'll see the red pulsing LED and the NeoPixel will be green that tells you its now in bootloading mode
- The Metro will show up as the Bootloader COM/Serial port
- The IDE should see the bootloader COM/Serial port and upload properly