Can I unplug a bootable usb after shutting down the computer?

If i were to boot ubuntu from a usb, could I unplug the usb and go back to my main OS after shutting down the computer?

Solution 1:

An Ubuntu live USB session does not change any of the files on any already installed OS by default including the bootloader, so it is safe to remove the USB drive after shutting down the computer. The next time your computer boots it will boot the main OS that is installed on your computer's hard drive as usual.

If you used the Ubuntu live USB to install Ubuntu on your computer's hard drive, then it also installed the GRUB bootloader on your computer's hard drive so that Ubuntu will be able to boot without the Ubuntu live USB plugged in.

By the way it is also safe to remove an Ubuntu live USB flash drive when restarting the computer after installing Ubuntu. Grip the Ubuntu live USB flash drive and get ready to remove it, then wait until you see the manufacturer's splash screen when the computer is restarting, and remove the flash drive right away before the computer starts to boot from the hard drive. If you know the BIOS/UEFI access key, you can also enter the BIOS by pressing that key, remove the flash drive, and exit the BIOS without changing any of the BIOS settings.