LR CC..PS CC....El Capitan with the latest Latest iMac.
Did you tried the solution in the link Lightroom and El Capitan | Mac OS 10.11 for Lightroom?
For Photoshop :-
Double-check to make sure the script is at this location:
/Applications/Adobe Photoshop CC 2015/Presets/Scripts/Photomerge.jsx
And that this folder is also present:
/Applications/Adobe Photoshop CC 2015/Presets/Scripts/Stack Scripts
Open the Stack Scripts Folder and Send a Screenshot.Also send a screenshot for contents of folders I listed above.
I had to turn off ''Show import , show add' in LR prefs...restart LR...
Then install the older...2015.16 PS from CC previous versions....Over the new one...
Then reinstall the new update...and everything seems to be working ok now
Thanks for the update.
Glad to know it is working now for Photoshop as well