Hello Noel

All transpose settings were checked and were concert pitch. I called PG and they told me that it is possible that files can become corrupt and become irredeemable. After trying their advice I simply abandoned the file.
No, closing the application and restarting has no effect on the song crackling once it starts.
"saving undos". I don't use the undo function much as I find it unreliable. In trying to isolate these issues once I tried 'restore to factory settings' - still crackles. When I used undo, I found that the previous non factory settings were not fully restored - for example the display changes did not undo back to "Allanah". As I have no idea what effects the undo function does or does not undo I avoid it.
I want to say that despite all this cranky programming, Real tracks are fantastic and BIAB is still my goto music app I use it way more than Cubase.
Z