I upgraded to Elements 11
So why post in a Forum dedicated to Photoshop?
The Photoshop Elements Forum might be a better one for your question.
Hi there! Because the forum you originally posted in is for beginners trying to learn the basics of Photoshop, I moved your question to the Photoshop Elements forum, where you'll get more specialized help.
Suddenly about a month ago, all that organization disappeared and was replaced by a long list of Tags which most definitely do not retain the organization I previously had.
Did you do anything at that time which might affect the organization? Such as importing photos into a new catalog (perhaps on a different computer)?
Another possibility is that you opened a different catalog by accident. You might want to search your hard disks for other PSE catalogs, which would be named *.pse*db. On Windows, you might have to tell Windows to search in hidden folders. If you find other catalogs (which would be a month old now), you could double-click on it to see if your organization is in there.
Thank you. I did get help from the Forum. Somehow my catalogue had been changed to another catalogue. That was the problem.