Go to your hidden folder for the catalog you want in My Pictures.
Find the following file:
Right-click on that file and choose: Open
Please check if that catalog is listed when you select either of the three locations in Manage catalogs dialog- i.e. Catalogs visible to current user, to all users and custom location. If this doesn't help, please look for catalog.pse11db file on your hard disk.
You will have two catalog.pse11db files; so you could send them to the desktop and re-name them as shortcuts for quick launch in future.
Many thanks for this solution which works perfectly. Still bemused why it's necessary but it works.