Uninstalling and reinstalling won't affect your presets or plug-ins so try that.
Check in Help / System Into to see how much video memory you have available to LR. Is LR somehow using your motherboard video instead of your video-card video driver?
Thanks for a quick reply!
I started Lightroom to check the answer to your question and was pleasantly surprised that for the first time I see that the "Use GPU" box s unchecked. Every time before this change did not survive the crashes. So that's good.
My Ivy Bridge desktop has 32Gig RAM and in the System info all of it is allocated to Lightroom, which is what I would want... it's the reason there so much in there! My GPU is a Radeon R9 200 which I believe is 2Gig VRAM. Yes there is an on-board graphics capability buy that is disabled at boot as a setting in my BIOS.
In a CC-provisioned machine, I guess I still use Programs and Features to uninstall Lightroom and then CC will "notice" the lack of both Photoshop and Lightroom and download the programs again.
But now that the GPU box is unchecked the CTRL-E external edit request is honored! Yea!
I will keep an eye out for that box becoming "checked" by ghostly hand in the future.
Spoke too soon. Still crashes as it tries to exit whether asked to back up the database or not.