I have several versions on my machines and can run them all concurrently. I use the Creative Cloud plan for all of them (that is, I do not run a pre-CC version along with the CC versions, but I did many versions ago w/ CS6 and the CC versions with no problems). You should also be able to remove and re-install all of the CC versions at will via the Creative Cloud Desktop app - on my machine, this goes all the way back to CS6. If you click on the down-pointing triangle next to the “open” button in the CC Desktop app for any version of photoshop you have installed, you can choose the “manage” option and choose to install “Other versions" of photoshop.
I just opened CC2015, CC2018 and CC2019 all at the same time on my Mac with no problems. For more recent versions of Photoshop, plug-ins live in a common location so re-installing them (or copy-pasting) with each new version is no longer necessary for most plug-ins. Scripts and that kind of thing may require new installation for each new version of PS, depending on the nature of the support files and where they need to live.
If you want only certain plug-ins to be available to a particular install of PS, then install the plug-in files in the local, version-specific plug-ins folder, not the common folder.
None of my installations of new versions have adversely affected a previous install. HOWEVER YOU NEED TO MAKE SURE THAT WHEN YOU INSTALL (“UPGRADE”) THE NEW VERSION YOU UNCHECK THE “REMOVE OLD VERSIONS” BOX from the “Advanced” options of the dialog that should appear when you choose to upgrade to the new version. You might also want to transfer your preferences to the new version as well, which you can specify in the dialog (checkbox). Here is a short video on YouTube that shows the dialog to which I refer, albeit for Adobe Audition CC - but the dialog is generally the same.
If you accidentally remove the old version (2014, for example) the application will be removed but your old PSCC2014 folder and the plug-ins folder inside of it should remain intact in your Applications folder. If you re-install 2014 it will re-install back into that folder.
Hope this helps, I apologize in advance if your specific platform or workflow might not conform to my experience. I cannot, obviously, guarantee that you will be 100% successful with no issues whatsoever.
Been bouncing around this subject for years. I work for a publishing company my job is to prep/correct/retouch all photos that print in our magazines. We print a host of niche magazine titles that print sheetfed and web. I process many hundreds of photos per month.
I run PS 2014 and use the Dan's panel several amazing plus ins. Works fantastic. I have a very specific workflow and many go to time proven methods that produce consistently good results. I haven't seen anything in any update since PS 2014 that would be enough benefit my specific workflow to go through the headache of upgrading and re-setting up my photoshop set up.
A glance at 2019 PS has me intrigued with several tools that finally would be of benefit to me. The new Content Aware(stunning! Check it out!), The Modern Undo, Blendmode preview, Color Wheel(uses HSB!) Auto Commit and 2x select subject have me pondering and upgrade.
I have gotten many mixed answers and I need to know 100% beyond a shadow of a doubt that I CAN RUN two photoshops completely independent of each other at the same time with no issues what so ever. Like they don't even know each other is on my mac. I've heard sure you can, I've heard no you can't, I've heard you must replace an old version and start from scratch and every combination you can think of. I LOVE photsohop, I HATE having to play around with something trying to make it work, don't have time or interest to do so. It needs to work, now. I have two versions of Indesign that work just fine and independent on the same mac. I don't have time to fix a train wreck.
Didn't know who else to ask. So what has been everyone's experience with upgrading PS? Can I run TWO versions with NO issues like I can with Indesign? Hopefully I can get a 100% answer and download and set up PS 2019 with doing ANY damage to my PS 2014. Thank you for your time.