Having the exact same issue with "Edit in photoshop" Was working fine two days ago.
I can open as smart object, and open in layers but not open in photoshop. images are not updating in LR and have to be manually imported after adjustments in PScc.
I still have CS5 on the machine, but closed down. My usual work flow is to import from my raw folder, flag what will be finals, then edit any global adjustments, take any to PS that require it, by selecting and right click open in ps, in this case cc. It will open, or open as a smart object, or open in layers, then normally I'd click to close and do you want to save automatically pops up I click yes, then go back to LR and da da the new edit is there. But just now it's not. It's putting it in same folder converting it to a psd file. But not showing in LR. I have to then go and import again from same folder anything that has been in PS I bet it's some simple tick box but I have been over and over it. Can't see what's wrong ?
How in the heck is this the "Correct Answer" to this annoying and persistent problem?
I recently upgraded to a Dell XPS 910 Desktop with a 500 MB SSD. The problem has for the most part gone away. I think that Adobe makes such "fat" programs that while they are waiting for your "pokey" HD to catch up they get lost. A more streamlined program would certainly help. When I was still on a machine with a SSHD it still couldn't keep up and sometimes had trouble even starting. You can buy an SSD of various sizes (Prices are coming down.) and install it as your prime drive with the programs on it. Adobe should issue one with each PS or LR program sold!.
No one has answered this correctly yet in spite of the Correct Answer labels.
I have read that un-install and re-install of Photoshop can fix this problem, but-
From personal experience with the same problem (if my memory is correct as it was some time ago!)
I used the Adobe Creative Cloud Cleaner Tool (link below) to clean ALL adobe detritus from my computer, then used the CC App to freshly re-install Lightroom, then Photoshop. I have never had the 'blank' Ps window again.
Note: have backups of catalog and all presets, etc, that are important to you, before running the 'Cleaner'.