This happened to me! My solution was to go to an apple store, buy one of their portable SSDs right there, cp everything on to the SSD (that didn't appear to use

This happened to me! My solution was to go to an apple store, buy one of their portable SSDs right there, cp everything on to the SSD (that didn't appear to use any additional space!), wipe the mac, and then rm some unneeded stuff on the ssd before cp-ing back and using their no-fee return to return the SSD. There were a few esoteric issues, but for the most part it worked.