Yes, I've done that and it says its in the common files but all I see there is the Anteras Harmony files. Maybe it's hidden? btw, I did a full uninstall/reinstall and it's still there and I even upgraded to Melodyne 4.2 and it still has problems. Is there a way to totally uninstall Sonar with no traces of former installations?
 
Als, BandLab said it was downloading all the files but I don't know where they are on my computer as I don't see them in my "downloads" file. Where are they?

This does not sound right. Unlikely the file is hidden. Assuming you have SONAR and CbB installed, make sure to run the scanner for each DAW. They both have their own VST Inventories in the registry. Try a VST reset in SONAR and CbB. This will clear the VST Inventories and build them from scratch.
 
There are clean uninstall instructions for SONAR but I doubt this is necessary. It varies slightly by product. Which version of SONAR is installed?
 
CbB (not confuse this with SONAR, CbB is a different product with its own install and uninstall process) installers are removed by BandLab upon sucessful install. BandLab Assistant uses %appdata%\bandlab-assistant\Downloads

Thanx for the info, I'll give these tips a try in a few hours. Gotta watch some sports now!

If it is still showing in the list, what happens if you click on it?

Just opened my last official version of Sonar, version 23.2.0 Build 45 {2017.02} - x64, and there is no AT Pro listed in Region FX! Nice to see, or not to see. But when I open the latest BL version, the ATPro is still listed in the Region FX dropdown as well as in the Cakewalk Plug-in Manager under the VST3 AUdio Effects as a registered Plug-in. However, when I highlight it, at the bottom of the page it shows it's file name which is c:\program files\common files\vst3\Auto-Tune.vst3. But when I go to that location, I can't find it.
 
While still in the Plug-in Manager, I select AT Pro then hit the "Exclude Plug-in" button but a pop-up appears that says essentially that the file should be in that common folder but it's not there because it may have been improperly uninstalled, etc. Then it asks if I want it removed from the registry, I select "Yes" and it proceeds to do nothing except the little blue circle spins for a few seconds then disappears but AT Pro still shows up as a registered plug-in and still appears in the Region FX drop-down list..
 
Any other ideas?
 
 

Base 57
If it is still showing in the list, what happens if you click on it?

It tries to create the region FX but instead, a pop-up appears saying the VST plug-in failed to load (800040002) c:\program files\common files\vst3\

Fixed it, I hope! I had been opening a song and then going into plug-in manager to fiddle around and nothing much happened.  I just went directly into Plug-in Manager under the Utilities tab and don't remember exactly what I did, but I know I reset all the plug-ins and it ran thru the lengthy scan but this time AT Pro was gone! I notice my number of registered plug-ins has dropped by 2, it was 227 but now it says 225. Hopefully, it works better now.
 
Thanx for all the help and now I'll try getting Melodyne 4.2? to work better.

I've always had to uninstall the offending program, then reset all vsts, and rescan. Wish there was an easier way.