My assumption is that it's only adding Library files to the Playlist when using My Computer, thus any files shown, but not in the Library are skipped.

Yes, that's exactly what I was wondering. It sounded like you hadn't scanned all your files to the library and thus it was only picking up part of the folder.
The Location node is the Library's representation of what's in the "directories". So, if it's on the computer and not in the library, it's under "My Computer".
If it's on the computer "and" in the Library, and you need a directory representation of what's in the library, it's under Entire Library > Location node.

Thanks for all your help!
Loading the playlist from the Library gets everything that's in the Library and quickly. But, since I've made a lot of changes to the music on the disk drive, it, of course, does not get everything as represent by what's on the disk drive.
I hadn't really understood the concept of the 'Library'. I'd just started building playlists from the 'My Computer' node and that seems to have created the Library along with creating the database needed for the playlists. And, that makes sense now... the Library represents the database and even still has entries for directories I've move/renamed on the disk.
I think what was happening is when selecting from My Computer is that MM has to populate the database first and I wasn't giving it enough time before sending to the playlist, thus only got what it had loaded at that point in time.
See now I could probably make an effort to have the Library (thus database) more closely represent what's on the disk drive. I see there's an 'Add/Rescan Files to Library'... will experiment with that.
Thanks again,
Jack

jcanoy wrote:Yes, I'm selecting 'All' from a directory (folder) under My Computer. What other way is there?

Try it from Entire Library > Location node > find your directory > all > D&D.

jcanoy wrote: [column browser] Don't really understand what it's good for?

It's just a simple way of browsing a library. Highly useful for those who don't want to mess with a tree and somewhat useful for those
who, on occasion, just aren't in the mood for the tree. Also, search is not likely to be used either if someone isn't sure of what they want.
It's main function is simplicity (when you just want to listen, but not sure exactly or have merely an idea of what you want during the initial stages
of being inspired to listen).

Yes, I'm selecting 'All' from a directory (folder) under My Computer. What other way is there?

Tried with ~13k files and it worked too. Are you maybe in the My Computer node when doing this?

There is no way to pull, however you can also select all the listed files and add them to the Playlist.

I have 4.1.11.1783. I did some search on 'Column Browser' and found how to toggle that on/off... seems to present a panel at the top of a playlist (but not 'Now Playing' nor a 'My Computer' directory. Don't really understand what it's good for?
Anyway, tried some more and sometimes all tracks in a directory 'All' go to the playlist, but just tried one that has 6025 tracks and only 1769 of the tracks went to the playlist.
Seems one has to 'push' entries to a playlist. Is there a way to open a playlist and tell it to 'pull' all the tracks from a directory into it?
Thanks, Jack

Tried with 1 and it worked as expected.

Are you on MediaMonkey 4.1.11 and do you have the Column Browser enabled?

Trying to 'send' a Media Tree 'All' to a new playlist, but not all the tracks appear in the playlist. Can I D&D all tracks to a playlist?
Thanks