Loss of recorded material

Windows 7. Audacity 2.0.4. Loaded by .exe. Program seems to be recording OK; waveform good; when exporting as .mp3, looking at the recorded material the waveform has been ‘deleted’ apart from the final few minutes; the timeline shows the correct length of the recording (say 3 hours) but the first large percentage has ‘gone’. Checking the waveform during the recording shows all is well. User for some years.Thanks, Mike

Do you still have the Audacity Project that this MP3 came from? If so, does it play correctly?

Sorry, I didn’t explain properly. While recording, the waveform moves along the timeline fine, and everything looks OK. When one stops the recording process (recording my radio shows for archive) and looks back at what has been recorded, say for the past 3 hours, the wave form for (say) 95% of the time has disappeared (straight line) although at the time it was recording totally normally. I confused the issue by mentioning the later export to .mp3, which has nothing to do with the problem - sorry. What I can’t fathom out is how the program (or computer generally for that matter) can ‘choose’ to remove sound that it seems to have initially recorded satisfactorily. Sincere thanks for your help. mike

Have a look in “Edit > Preferences > Directories”.
Ensure that Audacity’s “temp” folder is in a location that is writeable and has plenty of free space.

Over 200 gb of free space available, so that’s not the problem. Used today, worked perfectly, recording a 3 hour programme. I would say that the problem only occurs 20% of the time. This is partly the bit that foxes me!! I can’t comprehend how the program can ‘delete’ what it has already apparently recorded OK. As I say, viewing the waveform during the recording process, all seems well. it’s only when one looks ‘back’ at the waveform after stopping the process is it that one finds it has gone. Thanks again for your time, Mike.

Do you have any disk/computer management tools running that may be trying to clean up temporary files from your computer?