Doktor Avalanche
Hijacked!

sorry about that, went barking up the wrong tangent
on topic: does the effected WAV play OK outside sonar? i.e., is the crackling embedded into the file, or is it something to do with playback on sonar

grove clip looping employed crossfading between segments in the past i assume it still does. possibly i have not checked, bounce to clip removes groove clip looping. if indeed the original was 24 bit no reason to add dither to process to 24 bit.  it is difficult to determine what is/was causing the problem without the project file.

Crackling happened whilst I was moving transport during playback. Dropouts would occur frequently, it was almost as though it was a huge latency issue until I rerendered the audio or used groove clips...
 
I'm going to check the WAV's again, otherwise I'm thinking was meta-information in the project file somehow got corrupted.

On the same project today and I decided to freeze some synths like Kontakt, FM8 etc etc etc...
Clicks and pops returned when moving transport around, and that was happening on the tracks I had just frozen (so same problem all over again).... NOT PLUGINS!

So guess what...

I did Utilities -> Change Audio Format to 24 bit again (remember this is already 24 bit project)...
And it went away again!

WTF?
 
Either I'm doing something really really stupid or Sonar is...
 
(I do have settings in project Preferences Audio Data: Record bit depth 24, render bit depth 32, Import bit depth original, but I can't see why this would be a problem).