Maximum PSE Organizer size?

@fricktronick, this thread is a few years old.  So to update it, I can say that my catalog now has over 250,000 files.  I do not use the Organizer's full backup feature to backup my catalog database and media files.  But I occassionally use the feature available in the past few versions which allows auto-backup of the catalog folder structure.  This seems to work reasonably fast, but others have reported problems (that I don't think is related to the size of the catalog).

I find it more reliable to simply copy the catalog folder to a different drive.  I also use other utilities to maintain and synch copies of my photo and video files on other drives.  One of the problems that exists with a large catalog is the number of small text files (.json and .xmp files) within the catalog.  These take an exponentially longer time to write to another drive than a single file containing the same amount of data.  For this reason, I find that it is faster to compress the catalog folder before copying the zipped file to the backup drive.  I then unzip the file on the new drive.   Even with the time taken to compress and unzip the folder, I believe this is faster than a straight copy.

Also, make sure that there are no missing files in the catalog before backing it up.  Go to Find>All Missing Files to confirm this.  It also doesn't hurt to repair and optimize the catalog from the File>Manage Catalogs dialog before performing the backup.

While there might not be anything in the code that caps off the overall catalog size, I have experienced issues with importing more than ~50k images at a time and backing up the catalog once it reached ~80k images. Basically I leave the processes running when I am not at my computer and then when back a few hours later it has crashed. Maybe just my system, but its a mid level gaming PC from a couple of years ago. Has anyone else run into these issues?

I'm new to Adobe Organizer after Windows Live Photo Gallery quit working, and I've lost my tagging twice on Windows Photo App- and I'm not a professional or anything.

Adobe has never published a maximum size for a catalog.  I currently have a catalog that has 175K media files.  I know of others exceeding 200,000.  There have been many improvements in performance over the years.  But there are also some newer drags on performance.  For example, the changes made in Elements 11, I believe, created whole new type of tags.  The media analysis that takes place automatically in Elements 2020 really eats up resources and can slow your computer to a snails pace while it is in progress.  If you are able to do so, leave your computer running 24/7 until the initial analysis (Auto creations, smart tags and face recognition) is completed.  If you need to work in the Editor and the media analysis is slowing things down too much, you can turn it off in the Organizer's Edit>Preferences>Media Analysis.  Auto creations seem to take up the most resources.

It is not recommended to have multiple catalogs.  And any benefit will likely be minimal.  Enjoy all the new features that you will see in Elements 2020.