Using build 20. There is a pretty major crash-bug in the editor. It comes and goes and I have not be able to replicate it. The bug results in a crash bug and corrupted scene file (which crashes on reload). This bug has popped up three times (on two projects) so far. It is really nasty.
I have published this crash bug with example (Case 640247)
Has any one else run into this ? If you haven’t yet, use source control ! You Might !
Yes I have had several beta 20 crash bugs. One was a scene corruption crash and seemed to be related to the scroll rect and prefabs
Yes, this happened to me and, being the newbie I am with programming and game development, I’m not too sure what to do about it. Do I have to just start over and take more frequent backups?
If so, I should probably at least wait until this issue is fixed. It cost me a significant amount of time and don’t want to go through that again.
Yes its a real worry for me too. Grab syncback and set it to backup every hour or so.
Same for me here. It happens when I disable a gameobject with RectTransform component and the switch to play mode in the editor; The stack trace of the Editor.log indicates this:
#0 0x0000000077783c in Transform::SendTransformChanged(int)
#1 0x00000000777a07 in Transform::SendTransformChanged(int)
#2 0x00000000777a07 in Transform::SendTransformChanged(int)
#3 0x00000000777a07 in Transform::SendTransformChanged(int)
#4 0x00000000777a07 in Transform::SendTransformChanged(int)
#5 0x00000000eb3d90 in UI::RectTransform::UpdateCachedRect(Transform&)
Then the scene file is corrupted. I opened a ticket on issue tracker also.
After some digging, my issue is related to InputField. And there is an existing ticket about that:
These issues should be fixed in b21 afaik. Is anyone still having issues?
Just updating now.
Seems fixed for me. Thanks 
Updated to 21. 21 fixed this bug, but now, I have a new bug.
This new bug seems related. It makes the app unusable. I am reverting to 20 for the time being.
Still having issues. My scene still hard crashes the unity editor even before I hit play. Filed a bug report (Case 642251).
Edit: I thought I was using b21. I was actually using b20. Bug got fixed as soon as I updated. Thanks UT!