I have Sampletank 3 and have the VST3 version installed (correctly) however I am not sure Sonar is actually using it, even though the option is selected in VST setting. Further, when I use the VST utility tool, ST3 does NOT show up in the list of VST3 instruments, even though it has been installed properly AND appears in the VST scanning tool as being installed and operative.
 
I have even experimented by removing the VST2 version to another location. Sonar then advises the VST for the project is not available, when it SHOULD be simply loading the VST3 version. So yeah, something odd is happening. Not to mention ST3 is also crashing Soanr every second or thrid time it is run and played around with (eg patch "surfing")
 
Thanks

Look at the top of the VST window for the little dropdown menu.  It will show either VST2 or VST3 here, depending on what you have inserted.
 

 

...and when selecting a plug-in, note that the icon next to the plug-in name in the Browser is different for DirectX, VST2, and VST3.

And in Cakewalk plugin manager, I can see that SampleTank3 is available under both categories, VSTi and VST3.
 
In my Sonar setup, I had to add "C:\Program Files\Common Files\VST3" to my VST scan path in VST settings.  So that would assume that is the location where you installed the VST3 during SampleTank installation.
 
I have all of my VST 2 plugins either in "C:\Program Files\Cakewalk\VstPlugins" or "C:\Program Files\VstPlugIns", so everything gets scanned in on of those three locations.
 
After verifying that your paths are correct, try the "Reset" button under scan options and scan them again.
 

Thank you to both of you. That got it all sorted. Seemed the VST3 version was actually set to disabled in the manager??

joden
Thank you to both of you. That got it all sorted. Seemed the VST3 version was actually set to disabled in the manager??

You may have done that because the vst3 flavor of Sampletank 3 had a history of crashing Sonar when it was released, not sure if it still does.

joden
I have even experimented by removing the VST2 version to another location. Sonar then advises the VST for the project is not available, when it SHOULD be simply loading the VST3 version. So yeah, something odd is happening.

Sonar won't load a VST3 as a replacement for a VST2 that is missing because they are two different plugins. It can only load a VST3 if it was physically inserted by you. Same works for DX vs VST versions.

I'm running the VST3 version of ST3 v3.7 in Platinum without crashes.  Not disabled here.
 
But come to think of it, I believe I had a few SampleTank crashes in Tracktion with the VST 2, so I have that one disabled over there and use VST3 exclusively.

There is a setting in Preferences that tells Sonar what to do if both the VST 2 and 3 version of the same plugin is installed. If you check the box Sonar will always use the VsT3 version.