I use my photos as references for the paintings that I do. So besides the "People, Places and Events" kewords I've created about 14 other Keywords to be able to quickly identify the subjects that I want to choose from. ie. Landscapes, Lighting, textures, patterns. That is what I meant by "User Defined Tags". After converting my catalog to 2018 I could no longer find those tags to try to search. They were no where to be found in the "Find" or "View" menus. I checked in "Preferences" and there was only a mention of tags but not how to get them in to view. Even searching online, I could only find information on "People, Places and Events" and no mention of custom tags (or user defined). I REALLY miss the old fashioned manuals that used to come with software. A quick search in the index would have answered my question but after a couple DAYS of searching, I've FINALLY found that I didn't need to rename anything and the only "Media tabs" I found, distinguished photos from videos etc. (no mention of keywords to be found there). All I needed to do was to click the "keyword/info" icon at the bottom right corner of the screen (I hadn't even noticed it there before) and then click on the heading "Keywords" and my "custom" tags magically appeared for the very first time in 2018. At that point I can do my usual searches. I hope this information will help save someone else the same frustrating search.