First half of project abruptly missing


I recently made a recording in the latest version of audacity for windows which was just over 11 hours long, however when i went to review the prodject the first 2/3 are deleted/missing. Audacity says there is heaps of disk space left (over 53 hours) so it wouldn’t seem that would be the case.

I want to make another recording but i cannot have this happen again. please someone help.

Here is an attached screenshot of what has happened.

Are you sure it wasn’t a little bit longer than that? You’re running pretty close to the maximum duration for an Audacity project. The longest project that can be saved and successfully reopened is 2^31 (about 2.1 billion) samples, which works out at just over 13.5 hours at 44100 Hz.

For any important recordings I would recommend Exporting the recording as a WAV file as soon as the recording is complete. I would particularly recommend doing this for recordings that are as long as this. Note that the maximum size for a WAV file is 4 GB, which is again around 13.5 hours at 44.1 kHz stereo, so you may need to Export it in smaller sections.

its exactly 11h 16 mins, says that in the screen shot, next time i’ll only record 1 channel, and i thought the 13.5 hour limit applied the the 32 bit version only. Anyway, this doesn’t explain why 2 thirds of it has dissappeared!?

When did the audio disappear? Did you save the project and then reopen it, or is that immediately after stopping the recording?

Which version of Audacity do you have? (Look in “Help > About Audacity”)

There is only a 32 bit version of Audacity. There is no 64 bit version (though the 32 bit version runs fine on 64 bit machines).

version 2.0.3

This is confusing me

In principle, the solution to recording over 13.5 hours is to use the latest version of Audacity. Here, samples are stored as 64-bit values (even on 32-bit machines), which at 44100 Hz sample rate offers a maximum recording length of a mere 58 billion hours. Whilst we believed 64-bit storage worked properly in 1.3.3 and later, some reports in early 2008 suggested that recordings were still coming up against the 2^31 limit. Our development code was fully converted to 64-bit sample counts in July 2008, so long recordings now work again from legacy 1.3.6 onwards, but only if exported as audio files before closing the project (see below).

There is no 64 bit version??

All i want to do is make a large recording of about 10 hours and save it? Why am i encountering this problem?

Audacity projects containing more than 2^31 samples will re-open empty with the entire data being seen as “orphaned files” (although the data “appears” to be in the correct location expected by the .aup file). Workaround: Before saving or closing the project, export the recordings to audio files of appropriate size, or cut and paste sections of the recording containing less than 2^31 samples to new Audacity projects and save those.
Note: WAV files cannot be more than 4 GB in size. That means 6 hours 40 minutes for a 16-bit stereo 44100 Hz WAV. Many applications won’t play WAV files larger than 2 GB (3 hours 20 minutes for a 16-bit stereo 44100 Hz WAV).

is this what has happened? its just removed it?

Is there an automated way to export as a .wav or .mp3 when this limit is reached

This seems a convoluted method for a simple task.

No, there is no 64 bit version.
That quote is only about the format of the stored samples:
It is not referring to a “64 bit application” or “64 bit version”. Audacity is a 32 bit application.

No, and there is no automated way to save a project either.

The 2^31 sample (13.5 hour @ 44.1 kHz) problem is a bug. We hope that eventually this will be fixed but for now you will need to either use the workaround or a different recording program. It’s not actually such a “simple” task. If were, it would be fixed by now :wink:

can you suggest a program that would suit my needs? (simple recording of medium quality of 9 or 10 hours)

Audacity should be able to manage 9 or 10 hours at 44100 Hz. The problem is when the length of the recording goes over 13.5 hours at 44100 Hz.
You didn’t reply if the problem project was one that had been saved, but if it was then the original recording may have been longer than the recording when it was reopened. The problem is that Audacity “looses count” of the samples when it gets up to 2,147,483,648. If you do go over this limit you should be able to export it as one MP3 or as 2 or more WAV files.

If you don’t need such high quality you could record with a sample rate of 22050 Hz and then you should be good for up to 27 hours.

Sorry the project was ‘unsaved’ then after 11 hours, i saved it as test2.aup. However when I went to save it, the first 2 thirds had disappeared like in the screenshot. during the recording i did monitor its progress and it was recording well during the first 8 or so hours.

Are there recommended options/setting for recording long projects? So far i’m going to try again with 1 channel @ 22khz 16bit.

I simply want to press record and forget about it for the next 10 hours.

And thank you steve for your help.

Audacity is not a good surveillance recorder. There are other applications that do a better job – like automatically rolling the recording so it grabs the latest 10 hours and deletes as it goes, and record and play/scrubbing at the same time.

As above, you have to pay attention if you want Audacity to go over long sessions – and if this didn’t come up yet, none of these tricks works on a full or highly fragmented hard drive. Space and stability problems blossom like flowers as the drive fills up.

So no, you probably can’t “push a button and come back in 10 hours.”


Would be recording on and SSD with 50+gb of space left. A surveillance type program would actually be ideal, but I know of none.

A quick Google search brought up Streamosaur
I’ve not used it but I have used Wavosaur (by the same people) and that’s a good program.
If you try it, please let us know what you think of it.

I didn’t find that when I was googling, I’ll give it a whirl, probably buried underneath all the SEO paid results.

Get back to you later with the results.