HI Katie, the operating systems installed on the computer have EFI files to boot in EFI mode. You don’t see the dual boot menu (the list of installed operating systems) so this issue might be caused by the fact that the Ubuntu UEFI EFI file is behind Windows in the priority list.
Which operating systems was installed on the computer first? I suppose Windows, so let’s try to invoke the Ubuntu Grub to allow us to make the operating system selection on boot up:
Boot into Windows 10, then go to the Command Prompt to open it (in Administrator Mode). Do as follows:
- Go to Start
Command Prompt
Right Click and "Run as Administrator".
- Type in the following command and hit Enter:
bcdedit /set {bootmgr} path \EFI\ubuntu\grubx64.efi
- Restart your system
Now, the GRUB menu should be loaded. Choose the OS you want to boot into.