Unity randomly crashes editing terrain in 8.3

Hi, I have a really annoying problem with editing terrain in Unity 8.3. It crashes- this happened a couple of times in the last few days. first time it happened right away the first time I started editing terrain in the hdrp. I thought, well it is still experimental and I am not really using it anyway. But today after several hours of editing in the new terrain setup for 2018.3 it randomly crashed again as I was trying to raise terrain. No error messages or anything, it just freezes up. Not just the Unity but my entire desktop, I cannot even get out of it with a ctrl-alt-delete, I have to turn of my computer and turn it back on again to get windows running. I cannot find anything similar happening to anyone else when I did a search so I am totally lost. Has this happened to anyone else? Any Ideas? Using Windows 10 PC, Nvidia GTX 970.
One other quick mention, today when it crashed even though I was editing terrain when it happened I had also just exported some trees from Speedtree 8 for the first time into Unity.

 

Okay I started a new project, it just crashed again while doing texture painting, this time unity just stopped working and not my whole system. No error messages just crashed. I just now reopened the same project an upon opening I get this message "Unable to parse file ProjectSettings/ProjectVersion.txt:[Control characters are not allowed] at line 0".