If you have the Live Suite, or any of Ableton’s add-on instruments (or the Corpus effect), you have to be extra careful if you’re transferring a Set to a user that doesn’t have the same instruments. The issue is this: any set containing unauthorized instruments will be opened by Live in Demo mode – which doesn’t allow saving. Ouch.
That means that Freezing isn’t good enough – you’ll have to Flatten the track as well. The trick here is that a) you may need to keep a copy of the original track for yourself, and b) you may also need to transfer the MIDI clips to your collaborator.
Therefore:
1) Freeze the track and then save a copy of the Set for yourself (as described here.)
2) Copy the MIDI clips to an empty MIDI track (as described here.)
3) Flatten the track with the Ableton instrument in it.
Phew! That was exhausting.