There seems to be a bug in Plugin manager. Yesterday, Sonar X3b informed me that a plugin lexrandomdelay.dll was not present in a Sonar X2a project I was loading. But it was present in the plugin folder, along with the other lex nonreverb effect plugins. I created a folder for the lex nonreverb effect plugins and placed all of them there and lexrandomdelay.dll was displayed in VST list.
 
Today, I did a offline install of Addictive Drums 32 bit. Sonar X3b scanned the plugin, it was on the count list. But when I looked on the VST instruments list it was missing. I did the same trick of putting the Addictive Drums dll in a folder. Sonar X3b did its automatic VST scan and Addictive Drums dll was present in the VST instruments list. The strange thing is that the plugin count stayed the same when the VST instruments list showed it was missing and when it showed it was present.
 
I later installed Addictive Drums 64 bit and that was showed up straight away on the VST instument list.
 
Has anybody else experienced this in Sonar X3b.

 
If you're using a Plugin Layout file, you have to manually add plugins to the layout to see them. Only if you aren't using a layout at all will you automatically see every plugin available, including new ones.
 
 

Also use the browser to see if it is really picking up all you plugins.