dual boot system can't boot from usb

Question

I have Ubuntu 15.10 and Windows 8.1 both installed on my PC and I want to boot from a USB just to check something, but GRUB does not give me any option to do so. The USB is bootable (I checked it with another computer).

How can I boot from USB? And does this have something to do with the GRUB configuration or something different?

Solution 1

Try to enable UEFI and boot again. It solved problem to me once. By the way I had problem where i couldnt boot not UEFI USB, reinstalling USB with Rufus helped me.

Solution 2

You need to select USB boot in your motherboard's BIOS. Usually there will be a screen that says 'Press Del to enter BIOS, F8 to enter Boot Menu'. Press whatever key corresponds to the Boot Menu, and then select your USB from that.

Also, make sure your computer's BIOS is configured to boot from USB. This will be a setting in the BIOS, usually labeled 'Boot Order'.

Comments

[Daniel]

It won't, because it can't. GRUB has no way of knowing what to boot off of a USB drive. You have to use the BIOS boot menu.

[NonStandardModel]

Try another USB port if nothing works. Maybe the port doesn't work correctly.

[damer]

thanks @paulis it worked for me, I switched from UEFI to Legacy mode and my problem was solved,but should I leave it on Legacy always or I should go back to UEFI once II finish with booting from the usb ??

[Paulius Mickus]

I'm glad you solved your problem ;) I dont really know, if I was you I would just switched it again to UEFI and only go to legacy when I need this USB. (assuming you wont use it very often)

[nsandersen]

UEFI..? There is an option in the BIOS called Secure boot, which cannot be disabled.