Hello I am getting desperate! I have recorded an oral history which runs to just over three hours. When I export the audio it takes about 5 minutes to export, but produces a file just 4.30 minutes long? I’m using Windows 10 - I think! If not, then it’s 8.
Sorry but we need accurate information. See this link How can I tell what operating system I have?
And what version of Audacity (see the pink panel at the top of the page).
In general terms, what you describe would happen if you had drag-selected 4 ½ minutes then used the File > Export Selection… (or similar) command.
Either click in the track to remove the selection, or if you want to retain the selection, use File > Export… (or similar).
Hello I am getting desperate! I have recorded an oral history which runs to just over three hours.
If you are exporting to WAV you may be exceeding the maximum WAV file size. (Most formats don’t have a limit but it can be a problem with WAVs.)
Depending on the sample rate, bit depth, and number of channels, a 3 hour file could exceed the limit (which should be 4GB but I think the original spec said 2GB). The file size field in the WAV header is 32-bits and it says how many bytes of audio are in the file. If you exceed the maximum value it can hold, it will “roll over” and the reported file size will be wrong (and player software will have trouble).
You can try exporting to MP3 (if you’ve installed the LAME MP3 encoder). FLAC should work too if it’s handy for you to play FLAC. FLAC is also a good “archive” format so you might want to make a FLAC even if you want to play the MP3.
Another possibility is that you are out of disk space on the drive you are exporting to. When Audacity has no more space to write to, it will stop exporting and leave you with a short file (which will still play properly).
Even that short file will take a long time to write if Windows is having to find places all over the drive that it can still write to.