Ardour crashing on switching plugins on or off

Dear fellow Ardourists,
I’ve been using Ardour 6.5 through 6.9 on various Mac computers (Mac mini M1 2020 [both arm64 and x86 builds] and 2011, MacBookPro 2011, MacBook Air 2012) and MacOSs (Catalina, High Sierra, Big Sur), but one really annoying thing that keeps happening is that Ardour sometimes crashes when I switch plugins on or off by clicking the little green button on the plugin inserts in the channelstrip.
At first I put that down to overloaded CPUs on my older Macs, or the data being loaded from external FireWire drives. But the erratic crash behaviour persists even on my brand new M1 Mac mini with surely enough CPU power and the data loaded from the onboard SSD.
So I am at my wits’ end here … Maybe some of you guys experience(d) the same problem? Or have I overlooked some setting either in MacOS or Ardour? I’d appreciate any hint!
That said, I thankfully never lost any data through those crashes, data recovery works fine.
Thanks very much in advance for any help,
Cheers and best,

What plugins? Does it happen with the ace plugins?

As third-party plugins I’m using Melda, Softube and Valhalla plugins. I have installed the latest Melda version (v15) this morning, and everything was fine for a few hours but now the trouble has started again, and Ardour crashes sometimes whenever I switch on or off a plugin.
As for testing whether the problem crops up using ACE plugins, I’d have to do a separate test run with those, but I’m afraid I haven’t got the time at the moment.

I’ve been using Softube plugins (specifically console1) a lot on macOS (10.13 and 10.15) while developing Ardour’s VST3 support and never ran into that issue. Actually this is the first report that I am aware of that bypassing a plugin can cause crashes at all.

Next time this happens, could you copy the crash-report that macOS generates? That might be helpful.

Perhaps there is something specific to your system that can explain this… maybe language-settting (in case it’s non english) or perhaps some conflicting library (homebrew?), but those are just wild guesses.


Thanks ever so much for your help!

I’ve attached a zip file of the process log as displayed on Terminal and the proper crash report – I hope that works. (Log exceeds the maximum character number for posts, so copying it into the message won’t work.)

And I have to report that crashes have been happening not only when clicking the plugin insert bypass button, but double-clicking the insert (to display the plugin GUI). This is very frustrating indeed.

As for language settings, I am using the German-language setting on Big Sur and Ardour. As for conflicting libraries issues, I wouldn’t know anything about that since I am not familiar with programming or kernel compilation or anything like that …

Thanks again, and I’m eager to hear what you make of it!

(Attachment Softube Crash is missing)

Oh, it seems the attached zip file was rejected. How or where do I post the large log file so you can have a look?

Most of the time using a text paste solution would work fine. Gist, pastebin, etc.


It took me some time to continue this thread … sorry. Now I’ve posted the crash logs here: Ardour crashing on switching plugins on or off -

In the meantime, I’ve installed the demo version of Mixbus 32C (x86) on my new M1 Mac mini: No crashes whatsoever, AND the dreaded flipped display of the Waves plugin GUI does not appear, everything is displayed correctly! (Drives me nuts on Ardour … that said, I haven’t yet tested the new Waves M1 release with Ardour.)


The crash happens in com.softube.ME1B_VST_AU_Protect_AU

So some softube Audio Unit plugin is causing issue when loaded in Ardour.

This also explains why others don’t experience the crash. It could be that it’s specific to the a given version of the plugin, or perhaps even only for unlicensed versions (“Protect AU”).

PS. You could try to disable plugin-discovery (so that plugins are not loaded on session-start). Then the crash may only happen if you explicitly load softube AU. Perhaps the VST2/3 does not have the issue?

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