Installing Plugins into Adobe Photoshop CC 2015.5 or later on the Mac

Note that as of this release Adobe has a new common install location for plug-ins for this and future versions of CC.  That location is: 

Computer/Macintosh HD/Library/Application Support/Adobe/Plug-ins/CC/

You should drag your plug-ins to the above directory when installing.

If you have copied the plug-ins to the old location and now have two copies of the plug-ins appearing, you can just delete the plug-ins from the old location which is:

Computer/Macintosh HD/Applications/Adobe Photoshop CC 20NN/Plug-ins/

where "20NN" is your version of CC.  For example "2015.5" or "2017".