# Troubleshooting Transfer You can’t drag and drop more than one hex file at once onto your micro:bit. If you try to drag and drop a second hex file onto your micro:bit before the first file has finished downloading, then the second file may fail in different ways. When the first program has been written to the micro:bit, the drive will disengage. If you drag and drop a second file at this point it may not find the drive and the second write will fail. The errors may look like this: **Windows**  **Mac**  Or it may appear that there are two hex files on your micro:bit so the micro:bit won’t be able to run multiple files. To rectify this, unplug your micro:bit and plug it in again. Make sure that your micro:bit appears as `MICROBIT` and not `MAINTENANCE`.