Releasing music without permission of session musician

[Jerome]

If none of the band members got paid - including yourself - then you can probably release the music. BUT - before you do I suggest you talk to the other members of the band. See what they think about the situation. If he is a permanent member of the band you are going to need his co-operation for gigs etc. And if the CD sells he will be paid anyway. If he played 80% of the concerts (how many?) he surely must have got some payment from that. You mention 'one of my bands' - how many are there? Also, you paid two musicians for their work on the album so really you should be paying the others as well, unless you have an agreement with the other members of the band that no-one is getting paid and any revenue will come from sales/gigs etc. But you would have to have that in writing. It's a tricky situation all right. Finally, try talking to the band member in question. Come to an agreement and get it down on paper. Quibbling about money is the number one reason bands fall apart. U2 have an arrangement that has worked for a long time. No matter who comes up with the songs/lyrics/riffs/ideas etc. - they all take an equal share of the profits. It's one of the reasons they are still together.