Booting into Solus OS I got stopped by a black screen stating I was in 'Emergency mode', given a few options. I noticed a few topics here with helpful information; however, in my case the solution was simple. I had plugged in my phone for charging before. I unplugged it from the USB port, restarted the system and all booted up as per normal. Thought I would share to avoid people diving into it deeper than necessary.

I do not know what causes this screen to come up when my phone is plugged in during boot. Feel free to clarify!

It's probably thinking your phone is a bootable device and trying to boot it.

as Justin said, your phone gets recognized as boot device, check in your uefi your boot order