As the log file weighs 345 MB, I used google drive to upload and share it to staff.
I was dragging frames and layouts in starter gui, which resulted into studio freeze.
A private message is associated with this bug report
Are you able to reproduce this, including without any user plugins?
Unfortunately, cannot reproduce this, the time it happened I did some specific combination of creating gui object and then re-parenting (dragging), this is when studio froze, however the bottom of studio and file dropdown was still responsive, so I could save my changes.
I thought logs could help, but 
I’m hoping it’s fixed if you guys made any changes regarding explorer on v.689, because I was actively trying to repro, but couldn’t