I am on a Mac running Catalina 10.15.6. I moved a catalog to an external drive improperly. I was able to reset the catalog location to the external drive. I then had to reconnect all the files, about 100,000 of them. It took me almost a week of manual and automatic reconnection. I then did a backup of the file structure only. At the end of the process I got a message that the catalog couldn't be found and to create a new one or open another. I opened another (I have 3), and then went through Manage Catalogs back to the catalog I had been working on. All my reconnections are lost. In addition, none of the files that I have imported since mid-November are showing. This is also true of my other catalogs as well, all of the files since mid-November are not in the catalog.