In my case when that occurred, I had to un-install and delete ALL references to ALL adobe programs, run a registry cleaner, reboot, then install PS and LR with the Creative Cloud app.
(I did save backups of important folders containing my presets etc before the clean-up.!)
Thanks, I use Mac OS X Yosemite. I uninstalled PS and LR and reinstalled with the CC app but that did not help.
I have the same issue. I was ok before the upgrade to El Capitan and subsequent updates in CC. Very annoying as it is slowing down my workflow enormously. Any solutions yet? I'm tempted to restore to Yosemite