Tried to save a project in Logic Pro 11.

It may also be necessary to ensure you're running the latest version of the official Logic package :)

Jesse, when looking at the crash report it appears the crash was in MIDI handling. Are you using SoundFlow with any kind of MIDI setup? And was this error a one-off or can it be reproduced?

Ever since I "upgraded" to Sonoma from Ventura, Logic has been behaving very erratically. Saving projects takes minutes, sometimes resulting in indefinite "not responding" (which requires force quit).

Is this related to SoundFlow? Can you reproduce that behavior only when SoundFlow is running? It could be that something related to Logic or a plugin you're using has regressed after the upgrade, and that SoundFlow merely becomes collateral damage.

Can you clarify this question? I have many MIDI devices in the studio, but I wasn't doing anything MIDI-specific when this happened.

What I meant is if you are using any of SoundFlow's MIDI features, ie. MIDI triggers or sending MIDI from SoundFlow to Logic?

I'm not sure. The only reason I thought it might be (or at least partially) is that one of the crashes in the crash log is sfbackend. However, this is the only time I've seen sfbackend crash recently, though I've had many Logic crashes, so it could be a red herring.

My guess is the Logic crash is due to a faulty plugin in the session, if not a crash in the system-wide MIDI handling itself (which then caused both Logic and SoundFlow to crash/beachball).

If you encounter any other SoundFlow crashes, please let us know, and equally if you encounter a more direct relation between anything SF does and your Logic crashes.

As far as we know from the current set of information, my guess would be either a plugin in Logic causing problems, or something in Logic itself, possibly related to MIDI. There's no current indication, based on what you described, that it would be caused by SoundFlow. The easiest way to rule that out is to quit SF and see if your issues stop occurring.