I am currently having this same issue with the new Arduino Create for Education App with our student's Dell 11 Chromebooks.
We are using: Version 63.0.3239.140 (Official Build) (64-bit)
It was working previously on Macs before we switched to the Create for Education App on the Chromebooks. It does upload at first, but then the error happens and it will not upload after that without changing Arduino boards
One of the sketches we are using is: Arduino Cloud (it's for the Adafruit Neomatrix light boards).