PC does not boot FAQ

Question:

My PC will not boot when my mbed Microcontroller is plugged in. What is wrong?

Answer:

Some PCs will attempt to boot from a flash disk if one is present. The mbed Microcontroller exposes itself to the USB host as a USB flash disk, and so some PCs will attempt to use it as the boot device. The mbed Microcontroller is not a bootable device, so the PC will either fail to boot or timeout after a while and boot from another device.

This issue is not specific to the mbed Microcontroller, it applies to ordinary USB flash drives too.