Directory Preferences

From Audacity Manual

Temporary files directory

• Location: Sets the location of Audacity's temporary directory. Audacity uses this directory whenever there is audio data that hasn't yet been saved as an Audacity Project. Exit and restart Audacity for changes to the temporary directory to take effect. Make sure your temporary folder is on a fast disk with plenty of free space. If you need to put it on a network drive, enable the Audio cache option (see below).

Auto save

Saves the current state of your work automatically on a time interval basis. This enables audio to be automatically recovered when you restart Audacity after a crash or power failure.

• Auto save a copy... Turns auto save on or off.
• Auto save interval: Reduce the interval to make saving more frequent. This will reduce the amount of audio lost if there is a crash between save points.

Audio cache

• Hold recorded data... Check this option if you need to use a slow disk such as a network drive or USB key for your temporary folder. Slow disk drives can't keep up with audio recording, so this option holds the audio data in memory until recording is complete. At that point, the data is saved to disk as normal.

If your drive does not have sufficient space, go to the Quality tab of Preferences and reduce the default sample format and if necessary, the Project Rate. Note that using this option for long recordings will cause Audacity to use a very large amount of memory for the data.