When I lost all Notes from my current database and rebuilding Outlook didn't help , I dragged the Notes from a 2-week-old database clone to a desktop folder where they were converted to html files.   

With the exception of the empty, current Notes part of the current database, everything else works perfectly.  I don't know how to import only  Notes without losing hundreds of new and changed Tasks, Reminders, Mail, and Contacts  that were incorporated into the current database over the past two weeks.