Exactly… Yes. I erase .last, launch Wavelab, go into audio connections to assign outputs (THIS IS POINT X), and it works… Then quit Wavelab, then Start Wavelab, and it does not work… The only time I opened the audio connection dialog was to assign the outputs after launching Wavelab at POINT X.
Please email me in PM the .last file when it works (while WaveLab is still open, after you closed the audio connection dialog).
And the .last file when it does not work.
I would then compare the files and maybe get an idea.
Thanks.
Ok - files sent…
Toader, Q: have you imported the same file into either track of the montage, one as Main, one as the Reference track? And then when you sort the playback issue temporarily by deleting the appdata file, have you compared the playback SPEED of either track?
I’m asking because my reference track (identical 16bit/44.1 wave file from a CD) vs. the main track, when auditioning either (blue ear applied/blue ear released), is playing faster that the main track. The printed waves are identical in the project, BTW. Really weird behavior here and this probably explains the crackling I am hearing. What in the world could cause two identical tracks loaded into the same project to play at different speeds?
Could you try this? (read below…)
OK, I found my problem with the speeding up of the Reference track: I have my Sample Rate window set to 48K. The Main track playback isn’t affected by this BUT THE REFERENCE TRACK is. Setting the Sample Rate to 44.1, and now the playback speed is identical with NO GLITCHES.
And I will add that beyond this weirdness of the Sample Rate affecting the Reference track and not the other, by clicking on the blue ear/listen button, everything behaves perfectly (clicking the Reference track ‘on’, the Main track is muted).
@toader: I will check your files on tomorrow.
@mr.roos: sample rate conversion is not possible with the reference track.
PG, OK, I understand.
I will do one of two things in the future while working on an audio montage: during playback I will turn the Resampling option off in the Master Bus or match it to the Project sample rate.
PG,
I also rechecked to make sure, but yes, I am also using Wavelab 10.0.30 on my side as well.
Did not find any fixes at the moment! 
Thanks,
Did you try erasing the file .last as explained in a previous email?
Hi PG,
Yes indeed I tried that. I’ve done the tests and prepared three .last files for you. One original not working at first launch of Wavelab (copied during Wavelab open session), a second one after close, delete .last and restart of Wavelab which is “semi working” after reconnecting audio connections (copied during Wavelab open session), and a third one after close, delete .last and restart of Wavelab (copied during Wavelab open session). All mentionned issues in my last two posts are reproduced every time. The “semi-working” is that the reference track playback (using a file or monitoring) gets output to the Main Playback Bus, but stutters very much, getting dropouts, cuts and sudden jumps in time during playback. On the other 2, either using a file or monitoring just doesn’t playback through the output, though all meters are responsing to it.
That might help, so I’ll send you a PM with these files.
Another thing that might help to pin point some issues here and that is tied to it, at least for me, is that to work around the problem of the Main Playback Bus at this time, I have decided to use the Master Section Playback Processing, and things got back to working properly as they should. Clicking on “Listen Alone” on the Reference Track does mute the other normal tracks and outputs the audio of reference to the master/playback section and out like it should.
Problem is here: I usually use an input bus to monitor reference tracks in Wavelab, and not an actual file in my session. Activating the monitoring and going through the Master Section Playback Processing is simply unusable… so much latency, crackles, dropouts, cuts, jumps, name it! That’s without ANY plugins on the master section there, and using an RME Raydat at all possible buffer sizes/latencies… low or high, same thing! That must be linked to the same problem somehow, but this is also an issue!
Thanks PG 
I am having the same issue on OSX 10.14.6 and Wavelab 10.0.30 build 116.
When I have the reference track routed to Main playback bus I cannot hear it when enabling Listen Alone. I still keep hearing the other track(s), despite the fact that they should be muted. Is there already any solution to this problem?
The current work around, is to use the 1st two device ports for the main bus.
But by end of the month, WaveLab 10.0.40 will fix this issue.
Thank you very much!
Awesome, glad to hear this. Thanks PG!