File Won't Open

I have a song file (.cwp) that won't open anymore, whether I try from within Sonar or from the Windows directory. The file was behaving just fine (opening and closing over the last few days) until I exported a mix. I got my mix, but now when I try to re-open the file to make changes, Sonar gets stuck. Furthermore, I have to restart my computer to get Sonar working again with other song files. Other song files work just fine except for the corrupted one.
 
I'm just wondering what methods might be available for getting into the file. I can recreate it easily enough from previous versions of the song, but that's just being lucky in this case.
 
That's the story. Other than that, when I did my export, I chose 24 bit rather than the default 32. I can't see how that would make a difference.
 

Thanks so much! The file opens in Safe Mode and I can figure it out from here. Much appreciated.