On my self built machine, leaving certain USB devices in will cause strange boot problems. For example:

If an older flash drive I have is plugged into the machine, the PC will hang at POST... removing the stick causes the pc resume boot normally. Other flash drives do not have this effect on the system.

If my usb wireless adapter is inserted, the POST process will stall for maybe 30 seconds before continuing. Another USB wireless adapter I have does not cause this effect.

This is related to a "USB compatibility" setting in the UEFI. Problem is, disabling it prevents me from entering SETUP as I use a USB mouse and keyboard. It is an ASRock motherboard with the latest BIOS version, by the way. Has anybody experienced issues similar to this?

edit: just noticed that the network adapter only stalls the boot process if the system is rebooting. A bootup after a shutdown progresses normally.

  • You could always use a PS2/USB adapter to plug your keyboard & mouse into the PS2 ports, if you have some. PS2 ports allow you to press more keys at once and have lower latencies, but you might not be able to use fancy media keys. – William Lawn Stewart Aug 12 '11 at 7:09
  • @William, actually, I find the opposite to be true. There are some keys on my keyboard that only work when it’s plugged in to a PS/2 port, not USB. – Synetech Aug 13 '11 at 0:09
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    Can you please provide me your Computer Specs especially the motherboard? I have noticed this problem majorly with some Gigabyte motherboards. – 10100111001 Apr 3 '14 at 3:50

Yes the USB wireless mouse and keyboard prevent a proper boot. Disabling in BIOS only helps partially. It also prevents a slave drive from appearing at all. Some mouses have a switch, which should be turned on only after Win loads, but unplugging the wireless keyboard is a pain. Makes you wonder if manufacturers and Microsoft ever talk to each other. Well I can understand not talking to Microsoft, but the user suffers in the process.


For the wireless adapter, try disabling the boot from network/PXE option in the BIOS (assuming that you never boot from the network).

For the USB drive, it sounds like it is having trouble initializing, so either don’t leave that in when booting, or disable the boot from USB drive option in the BIOS (again, assuming that you never boot from USB drives).

  • Thanks for the response. Unfortunately network boot is disabled already. Interestingly enough, the wireless adapter only stalls the boot process if the system is rebooted. A shutdown and startup boots normally. – ElvisFanTCB Aug 12 '11 at 6:09

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