? in mp3 file name for playlists doesn't work

[simoncn]

I will try this using a Mac to see if it makes any difference. I might not be able to get to this for a couple of days.

When using the Mac to copy files to the Synology, is the Synology library shared on your network using AFP or shared using SMB/CIFS? What version of macOS is the Mac running?

It seems clear from your previous post what is causing the ? problem (an invalid Unicode character in the filename in place of a real ?). What is not clear is how the file on the Synology ends up with this character in its filename. I suspect this is something to do with how you are copying files from your Mac to the Synology.

I can't see what could be causing the problem with SS_S as a folder name.