I want to use various plugins in O7 Standalone.
 
By default O7 scanned c:\Program Files\Cakewalk\Vst Plugins, which did pickup some plugins, but not all and none of the Waves or Melda Production stuff I have.
 
I looked at the VST Scan folders I have in Sonar and added those same paths to the settings in O7, but that didn't work.
 
Am I looking for the folders with the .dll files in them?
 
Any suggestions?  Thanks.

I think you need to point the scanner in the direction of Program Files (x86) , as opposed to Program files (no 86). They should be in there and be picked up by the scanner. 

Just look in Sonar Preferences/VST and see which paths are being scanned for logins and use them in Ozone.

Waves plugins will not work in ozone 7 with a PC because of the shell waves uses. I have my reply from tech support that I will paste for you when I get a chance. They will work if you are using a mac. This is why I'm staying with OZ 5. It was a deal breaker for me.

At the top of this section of the forum is a section called Utilities for Sonar (or something like that).
 
Go to that section, and scroll way to the bottom.  You'll see a tool called VST Inventory.
 
Run that.  It will show you where everything is.  It's pretty helpful!
 
Our friend Bitflipper put that together for us to use.

You can get Waves plugins into iZotope apps (RX/Ozone) if you use a VST Chainer plugin that supports VST Shell plugins (I think Blue Cat's PatchWork will do it http://www.bluecataudio.com/Products/Product_PatchWork/ ) or if you have ninja skills you might be able to get shell2vst configured and working.  I went the shell2vst route, but I'm not sure I'd recommend it.
 
http://www.xlutop.com/buzz/ under "More Downloads" http://www.xlutop.com/buzz/zip/shell2vst.zip
 
Your missing Melda plugins might be if you only installed the vst3 versions, I'm not sure iZotope does vst3 either.  Need to install the vst2 versions and match the 32/64-bitness of the iZotope app you are running.

O7 picked up some Cakewalk plugins like the CA-2A, the IK Multimedia stuff, the Nomad Factory BT's, the Blue Cat free pack, as well as some other freebies like the Slick EQ from TDR.  Based on that and your input, it appears O7 doesn't play well with Waves and VST3's.
 
Dang-nabbit.

mudgel gave the best answer. Just open the Cakewalk Plugin Manager and note the search paths it's configured for. Duplicate those in Ozone (click Options and go to the Plug-in tab to add additional folders). Any plugins that don't show up on Ozone's "Plug-ins" tab after rescanning are going to be those that Ozone has rejected for some reason. 
 
The documentation only says that "Ozone 7 supports VST and AudioUnit (AU) plug-in formats". But if you go to the iZotope support pages, there is a compatibility list that explicitly excludes Waves and UAD plugins as incompatible. It doesn't mention VST3.
 
Curiously, it also excluded my Meldaproduction products here. Don't know why.
 
Also note that O7 will also exclude plugins that are locked to a specific host, such as ProChannel as well as any plugins you have that are restricted to other DAWs.

Thanks for the information.
 
I tried all of the plugin folder paths and tested the plugins that O7 did find.  (Some of those are proprietary and only work within Sonar as expected.)
 
And here I was hoping to be able to use O7 like the T-RackS suite, but with my plugins of choice.  Had I known, had I read the fine print, I probably would not have gone for that O6/O7 deal, since I moved away from O5 as a mastering option.
 
Hopefully this thread will help someone avoid the same erroneous thinking.

I had mixed feelings about the standalone application. At first I was excited about it but as I built up a practice project out of random wave files I gradually realized that my old process of mastering within a separate SONAR project gave me greater flexibility.
 
So it's back to using Ozone only as a hosted plugin. Very, very satisfied with it in that context. (I, too, had been moving away from Ozone for the past few years.)