Brian, Hi:
I solved the [Library] field problem. MC22 decided not to carry forward my previous settings ,by defaulting to 'main library' and ignoring previously-defined libraries. That aside, I am sincerely interested in reasons why my approach is not proper so that I may think about the problem in, perhaps, a different way and possibly consider a different perspective.
Currently, my digital audio library exceeds 87,000+ tracks. I have a 'flac' library, which resides on a 4TB HD and a 'mp3' library, which resides on a 2TB HD. The 'flac' library is my primary source. The 'mp3' library is used for 'portability during travel' uses on a notebook computer as well as flash drives which are used in my car (think handheld synchronization).
My backup process for the flac library pushes the content via 'Syncback' to additional 4TB HDs which are mounted on a docking station, commonly referred to as a 'sled'. I rotate the 'sled' versions offsite to a friend's home on a periodic basis to ensure to the backup drives are not co-located with the primary source should I experience a property disaster which affects the primary source. This is just Disaster Recovery 101 stuff.
I decided awhile ago to physically split the formats within the same music server for ease of management. I find having two instances running and displayed separately for each library helpful during a 'CONVERT FORMAT' operation and the subsequent verification. I have discovered on several occasions the existence of convert errors. I actually have a defined process involving a Microsoft spreadsheet which compares the library output (names and sizes) of the 'flac' and 'mp3' libraries to ensure proper synchronization.
I have never had any issues managing these two library formats in this way. Again, I am sincerely interested in your thoughts, which may improve my approach.
Lawrence