It did that when I tried to save a completed podcast as a wave file. Audacity wouldn't open it for conversion to mp3, and even said it was opening an mp3, which it wasn't. Even when I chose "Broadcast Wave" Audacity did the same thing, acting like it was an mp3 and acting like the file was not really opening. This is a big file, almost 3 1/2 hrs long, maybe that's the problem. Split the file in half? or could there be some other problem?

When SONAR determines the file size exceeds the RIFF Wave size limit (~2GB) it will create a Wave-64 file. See page 240 of the SONAR Reference Guide pdf for the write up on Wave-64. To save the file as a standard RIFF Wave, it will have to be exported in pieces or reduce the sample rate/bit depth to get the export smaller.

Thanks!

What you can do is split the file into 2 parts, encode each separately and then concatenate them into a single MP3 using something like mp3wrap.