May I ask there are songs from Spotify but after transfer to Deezer but no songs found in Deezer?

hello there @Minachung 

spotify advertises 80 million tracks, deezer 90 million.

what’s more likely if you’re migrating a library from one to the other is that the migration service is missing matches. this can happen for a number of reasons, and some services are worse than others.

i usually just search for the missing tracks manually after i’m finished.

sometimes agreements between labels can also come into play. neil young, for example, pulled his entire catalog from spotify.

ultimately, there may be some catalog differences at the end.

I’ve found that as well. I’ve used tunemymusic to transfer. But i’ll also let soundcatcher grab the songs and I have found most of them.