I had a problem with Lightroom opening my backup copy of Photoshop on a backup drive instead of the primary hard disk application when 'Edit in Photoshop' was selected.
I deleted the Photoshop.plist file as suggested by many threads but it made no difference, so I deleted the backup copy of Photoshop.
Now Lightroom will create a PSD from a Raw file when 'Edit in Photoshop' is chosen, but it does not open my copy of Photoshop, or open the file in Photoshop if the app is open already.
Any ideas anyone?
Lightroom Adobe Lightroom 6.8 Camera Raw 9.8, running on Mac OS X El Capitan 10.11.16
Photoshop CS6 13.0.6 x64
Reinstall PS CS6.