Two and they both lead to the same app in the apps folder. This does not happen every time I open a file, however. It has happened exactly twice or not enough times for me to detect a pattern. I know that the second time I noticed the behavior, I had opened an all vector PDF with Photoshop using the Finder's contextual "Open With" menu (and selecting Photoshop from there). Thanks. A.C.
A week ago, I upgraded to the new CC 2018. After the upgrades were all done, I dumped all Library items and other such "left over" data from my Mac. After that all works well except that twice now, I noticed that opening a new .psd document will open Photoshop CC 2018 again (?) although the second instance starts up with the "factory-set", default Preferences. In short, I have observed two (2) Photoshops (both CC 2018) running at the same time (but I only have one Photoshop installed on my single-account Mac). VERY odd. Incidentally, Acrobat (which was not updated) has done the same thing a couple of times, also with factory defaults.
Confirming this is happening on my installation of CC 2018 as well. This occurs in Photoshop, Indesign, and Illustrator. I have installed it on a brand new MacBook Pro 2017 15 inch with a Wacom Cintiq 16inch. It seems to be some type bug, def one I never come across in all my Adobe years. Looking forward to any solution to this on a backend side.
To make my files open in one instance of the program I have to manually locate the file in finder and drag it into the current window. Hope this tip helps anyone that is running into this issue.