Help on recovering long recording with corrupt .aup file

Hi, I have a bit of a problem with the recording we made at our church this morning, and which has for some reason corrupted.

We’re using Audacity 2.0.3 on a Laptop running Windows 7 64 Bit SP1.

Previously we haven’t had any issues, but we were only recording around half an hour and then directly exporting to MP3 (without saving the Audacity Project). Last week and this we have recorded the whole service, around 1 hour 45 minutes and saved as a project, to allow me to extract relevant sections of the service to MP3. Last week’s recording worked fine and is saved and can be opened, but today I went to re-open (after apparently saving OK) to get a message saying Audacity found 16,740 orphan block files. The .aup file is 2Kb long, which I know is an error as last week’s was 366Kb.

The audio appears to have recorded OK; there is around 17Gb of data (I know as I just backed it up!) with around 16,740 separate .au files.

I’ve looked at the restore options from the FAQ etc, and these seem to be OK for small projects, with manual stitching of files back together etc, but I haven’t got the time (or patience) to sift through the number of files I’ve got. Tried the auto repair tool but it didn’t seem to work (presume as it’s for an earlier version?).

I guess what I’m asking is whether there is a quick(ish) and easy way to restore my project, and also what might have caused the corruption of the .aup file.

Haven’t really played with Audacity much (aside from recording) so would be really grateful for any help as I’m not an experienced user.

Many thanks in advance


You may have no show. The AUP is a text file (you can open it in Notepad) that contains the instructions of what Audacity should do with all that stuff in the _DATA folder. Between missing a good AUP file (apparently) and also having bad blocks, there may be no way to put back together what’s left. The other elves will be along.

We recommend Exporting as a WAV file for archive and safety. It takes longer, but it’s much more robust. It doesn’t have to encode the work, so it’s much faster than making an MP3.

You shouldn’t re-edit an MP3, that’s for delivery only.

With a show that big, what’s the possibility you’re running out of drive space? Audacity shouldn’t have troubles with shows up to about 12 hours, so the show length should not be a factor unless you’ve been recording at rates much higher than 44100, 16 bit or 32 floating.


Hi, thanks for the fast reply. I kinda guessed that this might be the case - having opened up both the corrupt and valid .aup file (the one from last week) I could see they were in effect an index, and frankly I don’t fancy trying to rebuild something with that many entries.

As far as drive space is concerned currently we record at around 44,100 I believe (either that or 48,000 but I’m on another PC and can’t remember), and I noted the message that I had about 300 hours of recording space left or something like that - there’s not a lot else on that particular laptop. I would have exported the file in the end, but saved the project file as a temporary measure until I got home to have time to then do the export. Think maybe I’ll both save the Audacity project AND export as WAV in future to be safe…! (Will also check the .aup file in future…) The eventual file that will be made publicly available will be an MP3 (which we wouldn’t re-edit).

Now off to break the news to the pastor that his sermon is available, but in thousands of teeny bits…

Thanks again


17 GB of data is far too much for 1 hour 45 minutes of unedited recording. At 44100 Hz 32-bit float stereo that should be only about 2 GB. So either you were recording at an excessively high rate or you were editing the recording extensively. What does the sample rate say in the corrupted AUP file?

If you were recording at an excessively high sample rate, the length of track you can save as a project reduces dramatically. At 384000 Hz, you can only save just over 1hr 30 minutes in a track. This limit is removed in the upcoming 2.0.6, but if you go over the limit in previous versions, all the audio is reported as “orphans” when you reopen the project.

That would not explain the AUP file being nearly empty. The AUP file could have failed to save properly due to a rare but long-standing Audacity bug, or your drive has some intermittent problem. If the AUP file only contains references to a few AU files, all the other AU files in the project’s _data folder will be seen as “orphans” because they are not in the AUP file, whether you went over the track storage limit or not.

If you never edited this recording before saving it, it is theoretically recoverable, but the “Audacity 1.2 Recovery Utility” will only work reliably on about 1 GB of data at a time (so no more than four “d” folders at a time). You will have 17 recoveries to make, and 17 or 34 recovered WAV files to manipulate according to whether this is a mono or stereo recording.

If you edited this recording before saving, the relationship of file timestamps to Timeline position of the audio is changed, and it is not recoverable without the correct AUP file.


Thanks for the advice above. I’ve had a chance to look at the files and for some inexplicable reason the recording was carried out at 352800! I shall be having words with the person who was manning the laptop on Sunday :stuck_out_tongue:

I’ve had a fiddle with the Audacity Recover tool and managed to recover one folder worth OK, so will chug through the other 60 odd folders. Again, many thanks!