Yipe! 4.9 Beta Crashes on Startup

Ostadan

I don't know what state I got it in, but it crashes every time shortly after startup.  It sets up the windows, but as I move the pointer, it dies.

Hardware is a Mac.  4.8 still runs without problems, so I don't think the GPU is in a bad state.  And the log file isn't helpful.

Tail of log.txt (not helpful):

2016-28-23 14:28:20.720 WARNING: libpng warning: iCCP: known incorrect sRGB profile
2016-28-23 14:28:20.720 WARNING: libpng warning: iCCP: known incorrect sRGB profile
2016-28-23 14:28:20.720 WARNING: libpng warning: iCCP: known incorrect sRGB profile
2016-28-23 14:28:20.724 WARNING: libpng warning: iCCP: known incorrect sRGB profile
2016-28-23 14:28:20.724 WARNING: libpng warning: iCCP: known incorrect sRGB profile
2016-28-23 14:28:20.725 WARNING: libpng warning: iCCP: known incorrect sRGB profile
2016-28-23 14:28:20.726 WARNING: libpng warning: iCCP: known incorrect sRGB profile
2016-28-23 14:28:20.733 WARNING: QLayout: Cannot add null widget to QGridLayout/
2016-28-23 14:28:21.927 WARNING: libpng warning: iCCP: known incorrect sRGB profile
2016-28-23 14:28:22.182 Executing startup script...

 

Is there anything I can manually fiddle to get rid of whatever 'state' it is retaining that is killing it?