Are you trying to switch from Lightroom CC 2015 (Cloud) to Lightroom 6.5 (standalone)?
I actually bought Photoshop Element 14 to compliment my current version of Lightroom 5. I lost all my organization of images and that has really upset me, some 50k images along with the editing etc. Yes, I tried CC on line in June and did not feel that the volume of pictures I take warranted the fee. However, I did like the added features to support Lightroom found in Photoshop. Everything worked well until the trail period ended, then I lost all of my files and could not go back to my original version of LR. Actually, the program is corrupt and will not open so I will need to reinstall.
Thank you for your consideration and any assistance you may offer.
What exact version of LR were you using, 5 or 6.
If 5 then it is still on your computer and all you have to do is open it.
If you are on a Mac look in the Applications folder.
If you are on Windows click the Start button and look for Adobe Photoshop Lightroom (it may or may not have a 5 in the name).
LR CC and 6 is labeled Adobe Lightroom, No Photoshop in the title.
I am using OS X 10.11.3 El Capitan
Lightroom is version 5, and the installed version no longer opens. I will need to reinstall.
I bought from Adobe Elements 14 to do layers.
Thank you for taking time to help.
It is still on your drive and an Icon for it, a OS X Alias shortcut for it, is in your Applications folder. Open a Finder window, click on Macintosh HD, At the top should be Applications. Click on that and look through the list of apps installed on your Mac.
You didn't lose all your files. No images files are stored in LR. LR only references them from where you placed them either before importing them into LR, by using the Add option in the LR import dialog window, or where you told LR to store them when you imported them from either the camera directly or the memory card from the camera in a card reader.
What I think happened when you install PS Elements 14 is you use the Element image management system and that system/feature Moved all your images.
LR 5 is still install on your Mac hard drive. Installing the CC version of LR does not remove any older versions of LR.
Also your original LR 5 catalog file is still on your drive. LR CC made a Copy of it and converted that copy to work with the CC version.
As for Elements and if you did use its image management system I have no idea as I have never used Element.
I have used the Adobe Element 14 Organizer. Not at all sure how it works yet. I also did find some of my LR files on the hard drive, but only some. I am still looking at all of the files in finder to locate. Thank you for your advise.