I’m Windows Vista or 7, but this should be a relatively general problem. Occasionally audacity will fail and when I bring it up after the failure will present a window that advises me that ‘temporary files have been found’ and then ask if I want to delete them. Well, it’s rare that I want to delete the recently recorded material, so I always take the ‘not delete’ option. Unfortunately when I look for a relevant temporary file there are none. I’ve done searches for ANY file that was created on my system on that day (and I have done this right after not deleting the temporary files) and come up with nothing relevant. Where does audacity hide these temporary files? Also, I started writing code in 1969 though I’ve not written code for money in over a decade… I’d like to see the audacity source code but when I’ve googled for the source code and then tried to download all the relevant material… it’s not there. Some help would be appreciated. I’m not used to open source anything so my skills at plundering code via the web are nil. Thanks for any and all help you can provide.
If the current project has been saved at any time, the temporary files will be in the project _data folder (created when you Save a project).
If the project has not been saved, then they are saved in the “temp” folder that is specified in “Edit > Preferences > Directories”. Audacity Manual
It’s here: Google Code Archive - Long-term storage for Google Code Project Hosting.
If you are interested in building Audacity from the source code, there is a guide here: Missing features - Audacity Support
Are you sure it says that? If so, you are using an obsolete 1.2 version of Audacity not meant for Vista or later. For example, 1.2 will often crash on Vista or 7 when you press Stop after recording.
Recovering temporary files from 1.2 means joining them together into WAV files using the 1.2 recovery utility - see Missing features - Audacity Support .
If you use the current 2.0.3 ( Audacity ® | Download for Windows ) it has an automatic crash recovery system ( Audacity Manual ) .
Please note 1.2 is now completely unsupported so if you try to build the 1.2 code but it does not build, you’re on your own fixing it. 
Gale