System boots me out every time I open it on my Mac

A little over a week ago, UE4.9 just stopped working on my computer. It had been working perfectly fine for a couple of weeks before that, but now I cant get it to stay open, I simply bring in a BPS or move an existing geometry and it suddenly throws me out. What can I do to fix this? Why did it suddenly stop working?

My computer: MacBookPro 15inch mid 2012, OS X Yosemite 10.10.5, Processor 2.3 GHz Intel Core i7, Memory 8 GB 1600 MHz DDR3, Mac Hard Drive 115.49 GB free, Graphics NVIDIA GeForce GT 650M 512 MB,

What I have tried:

  • Opening a band-new project (soon as I delete existing geometry from startup and bring in a couple of BPSs, the thing crashes)
  • Closing all other programs on the computer and all internet windows and everything running in background, in case it was a RAM issue (same result of being kicked out)
  • Restarting the computer aka powercycle (no luck)
  • Opening my original project and the brand-new project(s) on someone else’s computer (file(s) will not open, suspect corrupted data)
  • Uninstalling and re-installing UE4.9 (no changes)
  • Uninstalling UE4.9 and installing UE4.8.3 (same results)
  • Running “verify disk permissions” on disk utility, finding some errors, then running “repair disk permissions” and re-running “verify disk permissions” and getting a clean read, then retrying to open one of the projects, new and old (still no luck, still boots me out few soon as I start clicking around)

So now I need to figure out why suddenly, after working fine for a couple weeks, it suddenly decided to stop working.

Thanks for any and all help!!!