When I add a song to my music it is unticked the next time I log in

[burryport]

I am trying ot get all of my local files into "My Music" so have created a playlist of local files.  I am going through the process of adding songs with "+" signs to my music but many of them revert back to "+" after I have "ticked" them the next time I log in.  For example, I'll tick all songs in a playlist, when I next turn on spotify many songs in the playlist will have reverted back to having plus signs next to them.

When I check My Music, some songs that have "+" next to them in the playlist are actually there, some aren't and some are duplicated.  Some that are ticked in the playlist aren't in My Music also!!!???  This is extremely frustrating.

There is also an issue with songs that are "ticked" not being consistant over PC, iOS and MAC.

Could anyone please shed some light on this?