Up to now I've kept my iTunes library (~8300 songs, pretty much all in mp3 format) all on my secondary computer, an iMac, because the HD on my main computer, a MacBook Air, is too small to hold the entire music library in addition to everything else.
I'm trying to add those local files to my library from the iMac. For songs in Spotify's catalog, it's all good, kinda. I can't add them to my library for some reason (even by Downloading them, it doesn't seem to change anything) but I can add them to playlists and play them, like them etc on both devices.
BUT with songs that aren't in Spotify's catalog (Bandcamp/Soundcloud downloads et al) I can't do anything except add to a playlist and play them on the iMac.
I've tried the following methods to try to fix this:
make new playlist and re-add the songs
try on a different wifi network (both are and always have been on the same home network)
create phone hotspot and try to redo it on that network
restarted both computers
None of these things worked.
How do get all of these songs into my library and able to play them on both computers (plus any other devices I might use) ?
You mentioned you've tried some troubleshooting steps to sync your Local Files, but would you mind taking a look at the steps in this article? Let us know how it goes.
On the other hand, keep in mind that you can only sync Local Files to mobile devices. If you'd like to sync them to another computer, the files must be saved on that one. These files can't be added to Your Library, but if you think this is something that we should implement, you can leave your vote on this idea.
Lastly, could you let us know if you're still unable to find the songs you mentioned from out catalog in Your Library when you like them or add them to a regular playlist? Are you experiencing this issue on all of your devices?
Keep us posted. We'll be on the lookout for your reply.