'Only a few files were affected' .. it would only take one file to cause this, and likely it is a codec.
In device manager you can look at your installed audio codecs to see if priorities have changed.

It could be that a standard windows codec was being used and Quicktime changed the priority to to the apple codec, or updated a codec or something like this. Sounds like it may be a bugger to track down.


I do not work here, but the benefits are still awesome
Make your sound your own!