I installed AT7, Friday and I'm getting droputs with it on a voice track.  There's not much in the AT7 manual about problems.  I have Auto Tune EFX and that does not drop out. 
 
Any suggestions?

I only use Autotune EFX for when someone demands it ("the" effect).  I use Melodyne for all serious pitch tweaking.  But, like you, EFX has never caused me any problems either.

Well, I tested it in Pro Tools MP9 (with the RTAS version) and there are no dropouts!

Something not set right in Sonar? or a problem with their VST?

I feel your T-Pain

Somebody wrote this - 'Just some more info. Opening the 32bit Sonar, Autotune works fine. Seems to only be a problem with the 64bit version'.

I posted on the Antares forum and I'll see what they have to say about it.

That was about 6 months ago so hopefully something has been sorted.

I have Sonar 64 bit installed.  Using Sonar 32 bit is not an option for me.   Although Pro Tools is still only 32 bit and maybe that is the answer?

There's a tutorial going cheap - $10 - There was a coupn code that may work to get even more off "mtsave50" - http://www.groove3.com/st...-tune-7-explained.html

I finally heard from Antares support.  They told me to up the buffer to 1024 as that would stop the dropouts, it didn't work.  Then they told me to install Sonar 32 bit as the Antares is not 64 bit, and I refuse to do that - the software must be compatible with my system, not that my system must be changed to be compatible with the software.  I'm in a hassle with them now trying to get a refund.