> I'm sorry to have wasted your time with my old hints ...

You'll never lose my time trying new (or old) stuff, as it's my fun and hobby :-)
And it's great having someone to exchange tips with.

> >For occasional small transfer through WiFi, I use free CX Explorer app
> I'm a long-time fan of MyPhoneExplorer for local sync of
> contacts+calender, file transfer over WiFi ...


I installed it, but couldn't find what use it could do for me, as contacts and calendar are already synced on the cloud, and CX Explorer works well for WiFi/Network/Cloud/Wired file transfer. Did I miss something?

Meanwhile, I rediscovered this morning a neat way to wired-copy music from PC to my phone. As my main music player/organizer/catalog is free MusicBee, I'll use from now on the sync playlist feature which I forget the mere existence. It's not as fast as Ztree to tag and move folders, but it does a nice job, it's more graphical as you can select by album covers, and it has additional features such as on-the-fly renaming/converting format to fits Android restrictions or to save space.

My music library is also indexed and available through Plex server, allowing to listen both stream and download offline on the road.

Still, a free, easy to use, MTP map drive utility that could work with ZTree would be nice.