I bought maybe the last Sonar Professional from the store shelf. It is version 23.10.0. build 14 2017.10. After installation I can't find TH3 or TH2 neither in Command center nor Plug-in manager. But I found in path C:\Program files\Common files\VST3\Overloud\TH3-64.vst file. How can install and apply or use TH3? Cakewalk VST scan path is referring to the place but still...no.
Neither I find no Boutique suite show up. What to do?
Best regards 
Japo

Hi, and welcome to this forum.
Try to do a vst reset and re scan (the last is equally important) in Preferences (P), File, Vst Settings.
All the best.

Zargg
Hi, and welcome to this forum.
Try to do a vst reset and re scan (the last is equally important) in Preferences (P), File, Vst Settings.
All the best.

On top of Ken's advice (if that doesn't work), you can try to manually add the path to C:\Program files\Common files\VST3\Overloud\TH3-64.vst
 

It is not a good idea to have redundant paths defined for the scanner. By default the scanner already looks at all the folders in "C:\Program files\Common files\VST3." The scan path may be verified in Preferences > File > VST Settings.
 
The Boutique FX Suite is part of Platinum.
 
TH3 Cakewalk was moved into the main SONAR installer late in 2017.
 
The plug-in should be listed in the VST3 Audio Effects in the Plug-in Manager. If it is not there it may have failed scanning but should have issued an error message during the scan. If it did fail, the plug-in would be listed in the Exclusion List. To view this list, click the VST3 Audio Effects plug-in category and "Show Excluded" radio button. The "Drum Replacer" is the only plug-in excluded by default.
 
A VST reset will clear and rebuild the SONAR VST inventory in the registry and may add the plug-in.

Great!
The thing was that when launching Sonar, the initial scan did not find TH3 but after resetting and rescan Sonar found TH3.
Big thanks and appreciation for your advice, Zargg, Mesh and Scook!
Japo from Finland, Miehikkälä