Exporting large files

I hope this hasn’t already been asked and answered somewhere.
In the last couple of days I’ve tried to record several hours of radio (from my built-in input).
It seems to record ok and sounds fine in playback in Audacity but when I export the project as an aiff file (I know that’s a very big file) and open that in iTunes I only have the beginning of the recording before the track stops playing. Yesterday I only had the first 19 minutes and today nearly 3 hours but I had recorded both days for 8 hours each time.
I also tried exporting from Audacity as a wav file today and opened that in iTunes. That opened ok as a wav file but was only the nearly 3 hours length I described before and not the full 8 hours i recorded.
I’m sure I used to be able to do this with no problems with an earlier version of Audacity.
Can anyone tell me what I’m doing wrong? Thanks very much.
I’m using Audacity 2.0.3 installed from the dmg and OS X 10.8.3 (and iTunes 11.0.2).

Different file formats have different file size limits (defined by the format, not by Audacity).
The size limit for “Microsoft PCM WAV” format is 4 GB (though this may be limited further on some (usually old) computers to 2 GB due to limitations of the file system).

I’m not sure what the absolute limit is for “PCM AIFF” files, but “Logic Pro” (Apple) states that the limit is 2 GB http://documentation.apple.com/en/logicpro/usermanual/index.html#chapter=14%26section=9%26tasks=true

The maximum size of an Audacity Project is limited by duration (in samples) rather than file size - currently 2^31 samples (just over 13.5 hours at 44100 Hz) http://wiki.audacityteam.org/wiki/Release_Notes_2.0.3#Large_Projects

For very long recordings, export in smaller sections, or export in a format that can handle longer duration (such as MP3, Ogg, FLAC, or a low sample rate WAV file).

Thanks for the reply steve, and for the information.

I understand the size of an Audacity project can be as much as just over 13.5 hours at 44100 Hz (what happens after that?).

I did a bit of experimenting and found I can export selections up to 6 hours and 45 minutes as either AIFF(-C) or WAV files to my desktop producing files of (up to) 4.29 GB on my desktop which open in iTunes as 4 GB. That seems to be the cutoff point. Anything longer or bigger just doesn’t behave, sometimes only playing a few minutes and sometimes a couple of hours, but never the whole length. So I’ll keep my selections shorter/smaller than that in the future.

Thanks again for your help.

Audacity can record much longer than that, but after the project has been saved, the project cannot be opened properly.

Audacity is a “32 bit application”, but internally it counts samples in much higher precision. I’m not sure off the top of my head, but it uses at least 64 bits to count the sample numbers, so it can go on working for very long recordings. The problem is with saving and re-opening the project the sample count runs out of numbers after 2,147,483,648 samples (this is a bug which will hopefully be fixed in the future).

Working with very long recordings can be a pain because everything tends to be slow, so hopefully you will find working with sections of “only” a few hours has benefits that balance the inconvenience. You may find that Export Multiple based on labels is helpful for splitting your long recording into smaller chunks.