Well now I feel stupid, but thanks so much, that did it. I'd set up an AutoPlaylist which I will use for sorting podcasts which aren't yet tagged properly or completely, but currently it contains all of them. Unchecked that and all working fine now. Thanks for the quick response too.

Not sure if this is the right place to post this as I'm not sure if it's a bug or something I've missed. However just in the last few days when wirelessly syncing MMA to MMW all podcasts are being downloaded (about 4,000), when I have Auto-Sync (--> Device) set to only select some podcast subscripti...

So you think it might be converting the files just to apply the volume leveling? I'll have a look at that. And MMW says is it converting the files when I sync them for the first time, and they lose their chapter markers.

Really sorry, I thought I would have gotten a notification when there was a reply. Anyway, I should have been clearer, but M4B to M4B. I'm on 4.1.21.1875, but about to download the new version. And the only auto conversion rule is incompatible audio to MP3, so I think that means the issue isn't ther...

I should have said it converts them to M4B again...

I've created some audiobooks from MP3s and added them to Mediamonkey, but when I sync my devices (a USB and a Note9), Mediamonkey converts them. After I first noticed this I changed the 'Supported formats on device' settings to include M4B, and ticked all the boxes in 'Supported format configuration...