I own Sonar 64 under Winodws 7 64b. I have the Autotune plug-in from Antares and in a first time I saw that the previous 32 bits version (Autotune Evo) of this plug-in refuses to work from one about month. I tried to download demo version of the new Autotune 8 (norammly fully compliant with VST3 64 bit) and it still refuses to work ! I took  contact with Antares support and they told me that it seems they have a specfific incompatibility with Sonar (I confirm Autotune 8 works fine with Wavelab and Cubase that I have too). Is somebody has the same probrlem ? (Last precision : the problem is not limited to Autotune, it covers all products from Antares)

Did they suggest what it is that is missing?
 
My concern is Waves Tune - which has some special navigation stuff using rewire together with normal VST - and Sonar never supported this properly.
 
Is Antares doing something similar?

You say it doesn't work but fail to mention how it doesn't work ?
Does it not scan the plug in ? Does it not show up ?
You should also list your Specs (OS type specifically)
 
And if you did go to support for Antares, im very surprised they didn't point you to this:
http://www.antarestech.com/support/documentation-detail.php?doc=Sonar_Platinum_Fails_to_Scan_Auto-Tune_8_38
For comparability issues with the plug in scanner itself:
Go to C:\Program Files\Cakewalk\SONAR Platinum
Right click on the Sonar application (SONARPLT) and choose ‘Properties’
In the Properties window, go to the Compatibility tab.

To give more precisions :
 
Here is the answer of Antares support to my last message : Auto-Tune 8 should work with Sonar Platinum. We have had some reports of Sonar Platinum freezing when scanning Auto-Tune 8 for the first time, however it does seem to scan successfully after a few tries, and then work correctly afterwards. We've reported this issue to Cakewalk.
 
 
The plug-in manager scan Autotune Evo (32 buts) but at the end of the scan, we can't see the plug-in (as some others 32 bits plug-ins which are supported now) but for Autotune 8, when it scans it, the process  stops on Autotune 8 and the scanning process is interrupted. I am obliged to do Ctrl-Alt-Sup ! The message of Antares suggest to dore more than one time... I tested several scanning... but the problem still exist.
 
Chuckebaby : I  see the message of Antares but I can't test it on Windows 7..; It seems exclusively adapted for Win 8 or Win 10...

Dupuy
 
Chuckebaby : I  see the message of Antares but I can't test it on Windows 7

Windows Compatibility has been around for many versions now.(it will work for Windows 7, 8 and 10)
Have you tried it ?

I have auto tune 8.1.8 and it works fine. Don't use it as much any more since melodyne! Win 7 64bit

ANTARES works for me

I have the latest version of Autotune 8 and it's working here under Windows 10.
When I first scanned it I had to run sonar under Windows 8 compatibility mode
(suggested on Antares web site at the time). Once it scanned then I could go
back to Windows 10 mode.
I think Antares updated version 8 since then and it is no longer necessary to scan
in compatibility mode.
At any rate, it scans and runs fine. Sonar Platinum.