Audacity crashes if you repeatedly split, change, join a track.

Repeatable on Windows 10. Latest build.
Issue: Audacity crashes if you repeatedly split, change, join a track.


  1. Download and Install the latest version of audacity (for this test I used 2.4.1 but I confirmed it already existed in earlier versions)
  2. Download notepad++ (you could also just use notepad)
  3. Make sure all your settings are default
  4. Download some random audio material that’s longer than 40 minutes. (The longer the production the quicker you will confirm these results) And import this into a new empty project.
  5. Create a second track for your convenience.
  6. Save this project on your local drive somewhere.
  7. Open Windows explorer to the folder created in step 5
  8. Change your folder view settings to details in order to see the file size. (If file size is still not visible add the missing column)
  9. Set this folder aside but in a way you can keep an eye on the size of the project’s .aup file.

    How to replicate the issue quickly:
    To replicate you will use the Selection Tool and Time Shift tool. Also Split activity and Join activity & Save.
  10. Select some audio (a minute or two) on the track created during step 4 of the preparation and split the audio into a few pieces.
  11. Re-arrange those pieces using the Time Shift tool (using an empty track makes this easier as you can move a section of audio to the second track while you re-arrange)
  12. Once all audio has been re-arranged and placed back in the original track. Select the entire track and use the Join tool so the whole track is merged back into one track with no splits.
  13. Save the project
  14. Look at the size of the .aup file mentioned in step 9 in the preparation.
  15. Repeat steps 1 through 5 several times.

After following these steps you will at first notice the project growing by just a kilobyte here and there but soon the size of the project increases exponentially. If done enough times your .aup project size will grow to a few megabytes until saves or really doing any activity takes so long the program hangs (possibly crashing if you keep going) while trying to save such a large .aup file.

Upon inspection of the large .aup file you will see a section of envelope points as referenced below but thousands of them.
And each time you replicate steps 1-5
At no point was the envelope tool used.

\ \ Interestingly, the only fix so far is to save and close the project. Re-open the project and make a tiny change like create a new track or move something by a frame and save. Suddenly the project shrinks back down to its proper size.

Hope these details are enough to reproduce.

Hi @geermanr,

Did ever resolve this problem? I’m getting it now in Audacity 3.3.2. I cannot split, copy and paste, and join tracks without the Audacity file growing huge and hanging.

Regards, Robert

Hey @geermanr, I found his thread on the forum that matched and resolved my problem.

You’ve probably resolved it by now, but just in case, here is the link:

Regards, Robert