I am experiencing the same problem too. But it didn’t start until I upgraded to the latest version of Vegas. So my wav files, all of them worked perfectly in Vegas yesterday and today they all do not. Some do and some don’t. I’ve reinstalled it and the same problem occurs. I have not rolled back to the older version to test. That’s next.
There is a problem in Vegas with .wav files and it is Vegas and not someones system. It’s a unknown cause that Sony hasn’t resolved. It also has the same problem in Sound Forge with the same .wav files so it’s a Sony problem and how they handle .wav files in their apps.
I know other people that also had a problem in the last version with .wav files. It’s a conflict with some other codec or app. Every other app I use can play or work with the files the issue is now only with Sony’s products.