3.2 producing abnormally large AUP3 files


Do any of you know how to fix this problem… I make a podcast and what normally would be a 3 or 5 GB file in the previous version of Audacity is now gradually increasing in file size as I edit. I’m actually cutting…not adding…so what I start with, say a 3gb file, ends up ballooning to 20 or 30 GBs as I cut things from my raw recording.

This is basically preventing me from working as I do not have enough space on my harddrive for this.


I wonder if you’re looking at the wrong numbers.

Audacity keeps a temporary cache as you edit. It’s not an AUP3 file (that I know of). In some cases, if you do a complex edit, it makes a copy of the whole show before it performs the edit. If you need to Edit > UNDO, it just steps back to the last known, good show. That’s why you can’t remove effects and filters out of order.

When you save the AUP3 file,it should revert back to the size you were expecting. Audacity doesn’t save UNDO — or at least it didn’t used to. Once you save the AUP3 and close the program, UNDO vanishes.

If you export a WAV of the show, is that enormous, too? I suspect not.

This would be a good place for a senior elf to drop by.

I do not have enough space on my harddrive for this.

That’s a different problem. You don’t have enough room for a 30GB working sound file? How old is the machine? What’s the size of the drive? I’m typing on a 6-year old laptop with a 250GB internal drive. If needed, I could push some of this work off onto an external drive and make a lot of room. Right this second, I could handle your production as is. 66GB available.

Do not try to work Audacity on an external drive. Only work on your internal drive. Once Audacity is closed, you can push files and work around as you wish.

How do you do backups?


This is a bit tricky because “this problem” might not be what it seems.
To avoid chasing off in the wrong direction, let’s just check to see exactly what “this problem” is, and then hopefully solve it, or at least find a workaround.

The “previous version of Audacity” was 3.1.3. Is that the version you mean?
This is important because:

  1. Audacity versions before 3.0.0 (released 17 Mar 2021) used a different format for saving projects, and managed the audio data differently.
  2. Audacity version 3.1.0 introduced “smart clips” with “non-destructive” editing.

Either of the above two changes could account for “this problem”.

Re: “1”.
The old project format (pre-Audacity 3.0.0) was a multi-file format.
The “project file” was a “.AUP” file, which contained information about the project structure, but did not contain any audio data. The audio data was stored in a separate “_data” folder. Typically the “.aup” file would be quite small, but the total size of the “_data” folder could grow very large.

Re. “2”.
The video in this release announcement shows “smart clips”: https://www.audacityteam.org/audacity-3-1-is-out-now/
Notice that some kinds of editing that would previously remove audio permanently, now “hide” the data but retain it in the project (“non-destructive”).

Also note that while Audacity is open, when the audio is changed, Audacity (all versions) retains “Undo data”. For example, if you select some audio and delete it, the deleted audio is retained on disk so that you can Undo the deletion. The “undo data” is cleared (removed permanently) when the project is closed. For this reason, comparisons of project size should be done when Audacity is closed, otherwise you may be looking at temporary “undo data” in addition to the actual project size.

One other thing:
Recent versions of Audacity have to do additional “housekeeping” before a project is closed. If these housekeeping tasks are not able to complete successfully (for example, if the computer is powered off while Audacity is still open), then this could leave large amounts of junk data in the project.

So this may be related to this issue here: Performance and file size issues when copying and pasting a small portion of a very large clip · Issue #3820 · audacity/audacity · GitHub which has been reported to the developers.

I am also seeing huge files. A previous feature of the same length was 200MB is now 5G. Would love to figure out what’s changed.

So it is likely you are carrying around some unwanted baggage. Generally, you can do a Tracks > Mix > Mix and Render on each track to remove it.

Just be aware that will also render any Pan/Gain settings or envelope settings that you have foe a track.


and that all audio clips in the track will be merged into one continuous track.

I have seen the same issue about abnormally large files in several threads, but everytime it gets dismissed. I have a file that only has 6 tracks and less than 10 min of recording and yet it is now over 18GB!!! I can’t save it anywhere and risk losing everything. I am confident it is an issue with 3.3.3 version as my previous podcasts didn’t have this issue. I will try and revert to a previous version to salvage and my files and my computer, but can people please look into this as a matter of urgency?