I initially had only one ground on my board, in separate polygons, connected by different vias. I wanted to separately make a Motor Ground (MGND) separate from my logic ground (GND). I took the ground wire from the power supply leading to the stepper motor drivers that was attached to a GND symbol, and renamed it a "MGND" from it's original name of "GND". I then renamed all the ground wires from my stepper motor drivers from "GND" to "MGND" to attach these pins to this separate ground. On the board, I renamed a polygon from "GND" to "MGND" so these pins have a place to attach too.
At this point, Eagle gave me a F/B error. I tried to reverse everything I did by renaming everything back to "GND"; the original ground wire from the supply, all the ground wires from the step motor drivers, and the ground polygon that I originally renamed. As far as I can tell, the schematic and board is exactly the same as before these errors occured, yet I still have major ERC problems. I screenshotted the error here:
I don't know what to do anymore, I've tried loading backup saves but none of them would work. Fixing these errors is basically my only hope now. I would really appreciate any advice, and can link my eagle brd/sch if needed.