Earlier today I successfully imported various mp3 and mpeg files into Audacity and played them (in order to work on some pitch changes). All went well.
At a certain point everything I imported started playing in a spritzing, distorted way. I even tried re-importing files that had worked earlier, same thing. Trashed Audacity and all associated files and redownloaded. Same thing.
Any ideas?
and all associated files
Did you? Reinstalling Audacity doesn’t reset Audacity. Audacity holds on to its settings and preferences in a hidden place so you can upgrade Audacaity without going through all the settings again. That’s fine until something gets corrupted and the corruption hangs around like a head cold.
Go > Go To Folder.
Trash the audacity folder.
I think doing that isn’t going to do any good because I think you ran out of drive space or memory.
various mp3 and mpeg files
When you import compressed files like that, Audacity uncompresses them and then works with them in a super high quality format. So they may have been tiny, convenient MP3 files outside, but they turn into huge WAV files inside, and if you did that multiple times, you have a stunning large production inside Audacity.
But wait, there’s more.
Every time you do an effect, a change or a filter, Audacity saves the whole show so it can UNDO if you mess something up.
So I think your drive or memory is on its knees and you just ran out of machine.
Koz
Thanks for the thoughts but I trashed all the related folders as per instructions on uninstalling Audacity.
My computer has plenty of power - I do protools sessions w 40 audio tracks without problem. And Audacity worked fine doing this earlier today.
Anybody else have any ideas?
You did not say what Audacity version you had and where you got it from. You can obtain the current 2.1.2 version from us here: http://www.audacityteam.org/download/mac.
Also see: Why do I hear clicky playback on Mac OS X?.
If you need more help, please tell us exactly what playback device you are using in Audacity (make, model number and how it connects to the computer, if it’s not the built-in audio).
Reboot the machine, if it is a long time since you did that.
Gale
I do protools sessions w 40 audio tracks without problem.
So that makes you a celebrity user. Most people don’t do that. Do you ever leave ProTools napping while you run Audacity?
Koz
Protools… 
You need to go on the hunt. Protools installs a kernel extension with “core audio” in the name. It ruins audio for all other DAW’s. It also pretends to lower latency for Protools, which I’ve never seen happen.
Delete this kernel extension. Restart the Mac. Enjoy hassle free audio in ALL applications, including Protools.
Lemme see if I can dig up the exact name…
It’s “AvidCoreAudio.plugin”.
It also pretends to lower latency for Protools, which I’ve never seen happen.
Did you try it on an Avid?
Koz
It’s an old trick.
I’ve removed that plugin on dozens of installations in the past. It used to give better (more stable) latency for Avid setups, but that is over ten years ago. Let’s say G5 era.
It still gets installed with older Protools, but doesn’t do anything, even for Avid HD setups. I believe the newest PT versions no longer install it. But, honestly, none of the people I support still use Protools. Avid is very near a complete breakdown and there are ample other DAW’s around these days that outperform PT in all aspects.