VOCAL SYNC - Rude Awakening

Does the waveform look highly distorted, i.e., hitting max level for extended periods of time? We need to narrow down what's producing the noise. Also this is a long shot, but try increasing latency temporarily.
 
Finally, did you call up the region whlie SONAR was playing? I noticed that SONAR doesn't like to do DSP while playing in some cases, for example, normalizing a lengthy section of audio without the transport being stopped.

Have you installed the Update 1 quickfix for Kingston? There was a problem with the 64-bit Double Precision Engine that was causing issues like that. Even if you have the update already, you might try disabling DPE in preferences.

After going against my nature, and reading vocal sync manual sections, I may not have been using or able to use as intended, also noticed the noise filter selection. I was thinking to synchronize more precisely somewhat different vocal sections, being some harmonized, do-wah, do-wah, do-wah's, with some guide,  lah, Lah, LAh, LAH's,
So I guess there's some restrictions there being, there not basically the same vocal lyric parts, there's some silence between both the do-wahs, and he lah's, 
I guess if need be Id have to do this manually, moving with snap off, or possible using audio snap in someway, or accept them as recorded.
So maybe this could be a warning to others, to read the manual first, or risk exposure to excessively loud screeching sound levels, LOL.
 
    

Same thing happened to me. I posted here about it. Noel was kind enough to check my file, and couldn't reproduce it.
 
For now, I don't think much about using Vocal Sync.

this is ... actually... kinda funny... 

FYI, I've had no trouble with Vocal Sync since the the UI tweaks and Manual Clarifications that arrived in the second or third Platinum Monthly Update.

I'm not knocking it at all, I've also used it successfully before, just learning its use, limitations, and consequences of going outside the box  (the hard way I guess :), and the value of reading help files first, I definitely learned my lesson, LOL, and was perhaps using it an unconventional way. If trying to reproduce Id suggest wearing hearing protection, or turn powered monitors or headphones way down. I guess the main issue is this seemed to somehow override manually shutting off audio engine, which I believe was my first reaction, and/or the main fader off first then audio engine icon, lastly I turned off audio interface to stop noise, so it seemed to somehow direct my audio interface to maximum output level, independent from Sonar setting. Noting I was somewhat in panic mode all occurring within a small number of seconds, I didn't wait to see if it subsided eventually.  
It may be also that I'm pushing the limits of my processor on this project as well, and from some of the comments seems you need to really isolate the tracks from any other FX processing while doing this. I've had similar things happening using Nectar 2 as well, it seems to need maximum latency and really hogs processor, but it usually shuts down the audio engine, or I can shut it off manually without resorting to turning off audio interface.

Nice Weimeraner, hope it wasn't deafened also. Having re-experienced this on subsequent attempts I usually now try and align (or misalign) manually using "shift-alt" in clip section to move, but more so if required I use Melodyne Studio, its a bit more meticulous, but precise time, tempo, level and pitch alignment. (if I don't get a good vocal take to start with). 
Cheers    

I thought it was just me, but this is what happened. Generally I have had no luck with any regional effects. It's a shame, I try them once or twice and then give up. V Vocal I think was the only one I ever had working. I always write it off as my computer is just not up to it as it's only an i5.  

I had the same problem today, and after reading all the above posts, I tried disabling DPE in preferences, as suggested by Brundlefly, that did the trick! So it looks like Cakewalk still have a problem with the DPE. I had already applied all the latest Sonar updates etc.
 
sevitts
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Windows 7 Professional
Intel i5-4690 3.5GHz
32GB RAM
2x 1TB SSD
Layla 3G
Sonar Platinum 2016.10
Melodyne 4 assistant
Cakewalk user since Cakewalk 4.0!!(for DOS)

Cactus Music
I had no clue what DPE was..

https://www.cakewalk.com/Support/Knowledge-Base/2005278/What-is-the-64-bit-Double-Precision-Engine-checkbox-in-the-Options-Audio-General or
http://www.soundonsound.com/reviews/cakewalk-sonar-5 jump to the "32 Bits Good, 64 Better?" box-out

I had that happen recently as well...the worst part is I had one of those snooty ProTools gurus in the room while it happened. He loves to pontificate on the virtues of PT/Elastic Audio/ Vocalign.
He witnessed that horrific blast and gave me THAT look.....
 
I love Sonar ( been here since ProAudio7) but sometimes it troubles me that I have to defend it in situations like that ( "I swear, this doesn't happen often!) :) 

GregGraves
I never have had this problem, use it all the time, and have never checked the DPE box.
So I checked the DPE box and used VS.  No problems.
Is this your scenario?  You have two vocal tracks, A and B.  You use VS to set up a region on B, but you never tell it to reference A, and then hit play?  Is that when the explosion happens?  If yes, I'd think that explainable by VS trying to match up B to the drums, bass, or nothing at all.  When I'm driving and let go of the wheel, I typically crash.

Can't answer for others, but in my case, no.
I read manuals and watch CW instructional vids before using a feature, so using it as intended.
Seems random, no pattern. Most of the time, it works for me just fine.
 

Add me to that list as well "Never had this happen".
I will see artifacts if I crank up the synch knob to high but like anything else in life... Things tend to get Funky when you juice it too much.