hello 
i’ve a big problem.
i record a file of 6 hours… i export the file in wav… 4.5Gb but when i listen i have only 40 minutes…
Someone can help me to recover the entire file?
The maximum file size for a WAV file is 4 GB. http://en.wikipedia.org/wiki/WAV#Limitations
If you no longer have the Audacity project that had the recording, try re-importing the file into Audacity using File > Import > Raw Audio… . Choose the same number of channels and sample rate that you exported at.
Now re-export in two or more separate WAV files by selecting each part and File > Export Selection. If you export at 44100 Hz and it is a stereo recording, export two WAVs of three hours each and they should just be below 2 GB each. Many players won’t play WAV files larger than 2 GB despite the 4 GB theoretical limit.
Some disk file systems such as FAT 32 on Windows don’t support any files larger than 4 GB.
Gale