Server Unresponsive

So I am still fairly new to SuperCollider, and I have hit a huge snag. For whatever reason, my server stopped responding, and sometimes it is just not working all together.

I am running SC 3.11 on Mac 10.15.5.

It has been working fine for weeks now, but for some reason today everything just… stopped. I was in the middle of trying an exercise and the server turned yellow. Trying to kill the server or reboot does nothing. Sometimes it stays yellow, sometimes it crashes with an error. I have tried restarting, reinstalling SuperCollider, and checking google for the answer.

Here is the error I get:

SC_AudioDriver: sample rate = 44100.000000, driver's block size = 512
Exception in World_OpenUDP: bind: Address already in use

And most of the time it is followed by this one:

Output AudioDeviceDestroyIOProcID failed 0x21646576
Server 'localhost' exited with exit code 1.

When it crashes. Sometimes it just hangs on the first one, unresponsive.

Currently, I can get it to work by plugging in my external interface, and it will even continue to work even after unplugging it. But the moment I kill the server (rebooting doesn’t ever work) it goes back to being unresponsive again.

Thank you in advance.

When you encounter Exception in World_OpenUDP: bind: Address already in use that typically means that you have an unresponsive server running in the background. Currently you need to “kill all servers” (in the menu) or run Server.killAll to stop it.

When the issue happens, are you using an internal soundcard? or external interface?
What is your system default input and output device?
Are you setting devices with s.options.device_("")?


Server.killAll will stop it, but when I boot it back up, it is still unresponsive.

The internal soundcard is where the problem is. If I plug in my external, the server will boot and operate fine, even if I unplug it while SuperCollider is running.

What’s weird is it just started happening yesterday. I executed a line of code and it stopped working. And it wasn’t even anything crazy, it was just an example about from a book.

I have set no options with s.options.device, I am using bog standard settings.

Thank you for the quick reply.

Post a lldb backtrace (with debug symbols) in a github bug report. Otherwise chances are pretty low anyone will solve this.

A bit of googling suggests that


has something to do with unplugging audio interfaces from Core Audio. Apparently your mac thinks you’ve unplugged your mainboard interface or something like that, even though it’s not physically possible. Actually, it seems it can happen when the sampling rate is changed too, which sounds a more plausible scenario for the mainboard audio.

But I see no good reason why scsynth should crash on those. So that does sound like a bug in SC.