Ubuntu – GRUB booting problem

For whatever reason (probably due to updating and Windows 10 using a different boot method or something akin to that) the listing of available operating systems has gone missing. This is something that can be fixed in a number of different ways. The simplest one to try is this:

• Open the terminal by pressing CTRL+ALT+T.

• Enter this command:

  sudo update-grub

• Press the ENTER button.

• Enter your password (no asterisks will show, nothing will change on the screen, the cursor will not move, this is normal).
• Press the ENTER button.

• Let the system do its stuff and then enter this command:

  sudo reboot

This will allow grub to automatically find and enumerate the available operating systems and then give you the option to boot to the desired operating system during the boot process.

I had the exact same problem. Stuck on the GRUB screen. No Windows, no Ubuntu! How I reached there? I wanted to remove Ubuntu, so I logged into Windows, deleted the Ubuntu partitions using Disk Management, then restarted my PC and got stuck at the GRUB screen.

All solutions that involve a Windows Recovery Disk (bootrec.exe and bootsect.exe) and those involving an Ubuntu live CD (boot-repair and grub-install) did not work. Should I have run bootrec or bootsect before I had deleted the partitions and restarted? I don't know. But it was too late now! Not until I found this hidden comment that saved my day.

I simply typed exit at the GRUB command prompt and was finally booted into Windows 10. As simple as that! If you want a "clean" boot into Windows, directly without having to type exit each time, then this is the procedure to follow. Once logged into Windows (after the exit from the grub loader), run cmd.exe with administrator privileges and use the DISKPART utility. No recovery disk needed. The procedure is detailed here, which is copied from here. I also copy it briefly down here in case any links are lost in the future.

1. Run cmd.exe with administrator privileges.
2. Run diskpart utility.
3. At the DISKPART> prompt, type: list disk then sel disk X where X is the drive your boot files reside on. To make sure which drive to choose, you can open the Disk Management GUI tool in Windows (since we are running full Windows version) not a rescue disk. In Disk Management, you will find Disk 0 is usually the boot C drive, and hence the one to choose. You can also recognize it from within the command line DISKPART> from its size. In modern systems, it is usually the smaller (or the only) drive, the SSD one.
4. Type list vol to see all partitions (volumes) on the disk.
5. Type sel vol Y where Y is the System volume (you find System written in the Info column in the previous listing). There is very good chance it is the only FAT32 partition. In Disk Management, it is clearly marked as EFI System Partition. You can match the size with the one that appears in DISKPART>.
6. Assign a drive letter by typing: assign letter=Z: where Z is a free (unused) drive letter. This is all what we need DISKPART> for.
7. Type exit to leave DISKPART>. Now we're back to the Windows (DOS) prompt.
8. At the cmd prompt, type: Z: and hit enter, where Z was the drive letter you just created.
9. Type dir to list the directories on this mounted EFI partition.
10. If you are in the right place, you should see a directory called EFI.
11. Type cd EFI and then dir to list the child directories inside EFI.
12. Type rmdir /S ubuntu to delete the Ubuntu boot directory.
13. Done! Restart and see for yourself a clean Windows boot.