How to troubleshoot a USB device that cannot be detected on computer boot

1. Older computers may not support the use of an external mobile device as a system boot entry, so they cannot be set.

2. If the computer can support USB device boot, it may be that the relevant settings are turned off in the motherboard, first of all to turn on USB boot device support in the BIOS, such as to find similar to "USB Storage Legacy supports" or "USB Storage Function" option and set to "Enabled".

3. The computer may be the USB drive to other devices, some motherboards will be categorized on the hard disk drive, you can select "HDD" boot, and then in the specific boot list to find the USB device name, and a part of the motherboard will be external CD-ROM, USB drives and other devices are unified to the mobile device, only need to set the startup item Removeable "(removable drive).