I am running a dual boot with Windows 10 on one M.2 SSD and Ubuntu 19.04 on another M.2 SSD (both Intel SSDs, different sizes).
I have set my boot order to boot the Ubuntu SSD as highest priority because I want to have a way of choosing what I'll boot (i.e. the usual GRUB choice to boot Ubuntu or boot using Windows boot manager) and I have GRUB installed on the Ubuntu SSD. This is typically what I get, however, on occasion (I'd estimate about 1/3 of the time) I get the GRUB command line, where I have to type "exit" before I am greeted with the usual GRUB interface and can choose my OS as usual.
This is made even stranged b the fact that if I manually select a boot drive (by pressing F7 with my BIOS) I am never given the command line, always the usual GRUB display.
Any help fixing this would be appreciated, because, while it does no real harm, it's just really annoying!
exit
in the grub command line is, that your BIOS will jump to the next entry in the boot order list. I assume you've chosen the wrong boot entry to be used first. Most probably this is a result from installing Ubuntu in the wrong boot-mode (UEFI vs legacy) and a succesfull attempt to repair the boot, but an obsolete boot-loader still exist.