This is another Session Drummer 3 problem.  I bought a new computer and installed SONAR and Cakewalk and I was able use Session Drummer 3 with no problems.  However I had to return the computer because of hardware issues and I exchanged it for a new one with the same specs.  On the new computer I installed SONAR and Cakewalk and Session Drummer 3 is not recognized by either DAW but it is recognized by my third DAW.  I did some research and I found that I needed to install the Microsoft Visual C++ Redistributable for Visual Studio 2012 Update 4.  I did install it and still no luck.  I did notice that right after the install and the first use of both DAW’s the VST Scan box that shows up in the lower right corner that says searching for Plugins it would show; for example, 24 plugins found but when I would open an existing project it would rescan and then show 22 plugins found.  I have other Drum VST’s to use but I need to switch other projects to the different Drum plugins.  Not a big deal but I thought I would just through this out there if anyone had any solutions.

24 plugins is awfully low if you've installed both SONAR and CdB
 
In fact this is the default set just for CdB
 
So.…. check your scan paths to make sure you're pointing them to the correct folders.

24 was just an example number. The actual number 107 plugins at first run but than opening a project it rescanned and then showed 105 plugins. Session Drummer 3 in in the correct folder. The folder it is in does get scanned. It's just not recognized by the DAW.

To be clear does it show here? 
 

Cactus,
 
Does Mr. Tramp have a wife?  

Cactus Music
To be clear does it show here? 
 

I went and installed Cakewalk by BandLab and its not showing there. SONAR Pro and Cakewalk show 113 plugins and SONAR X3 shows 114 plugins.
It now shows in SONAR X3
Yes it does show here in SONAR X3 but not in SONAR Pro or Cakewalk by Bandlab.
 

Jesse G
Cactus,
 
Does Mr. Tramp have a wife?  

 
Ha Ha, Mr Tramp is a Wurly VST and the best I've ever used. It's one of the few 32 bit plug ins I still keep. You also see the Poly 800, that was my first synth and it's so cool to still have those classic Poly synth sounds. 
 
 

Liquid Noise

Cactus Music
To be clear does it show here? 
 

I went and installed Cakewalk by BandLab and its not showing there. SONAR Pro and Cakewalk show 113 plugins and SONAR X3 shows 114 plugins.
It now shows in SONAR X3
Yes it does show here in SONAR X3 but not in SONAR Pro or Cakewalk by Bandlab.
 

Open up the plugin manager in X3, highlight your instance of Session Drummer - note the path under filename at the bottom
 
This might provide a clue as to what's going on

Bristol_Jonesey

Liquid Noise

Cactus Music
To be clear does it show here? 
 

I went and installed Cakewalk by BandLab and its not showing there. SONAR Pro and Cakewalk show 113 plugins and SONAR X3 shows 114 plugins.
It now shows in SONAR X3
Yes it does show here in SONAR X3 but not in SONAR Pro or Cakewalk by Bandlab.
 

Open up the plugin manager in X3, highlight your instance of Session Drummer - note the path under filename at the bottom
 
This might provide a clue as to what's going on

The path is correct. I'll keep working on it to see if I can fix the issue. At least I have other drum VST's.
Thanks for all the help.

Not sure what SONAR Pro is. My guess is SONAR Professional. If this is the case, all three DAWs have their own VST Inventories built by the same VST scanner. Hopefully CbB was the last DAW installed. This insures the most recent shared utilities are available.
 
There has been no mention if the plug-in is in the excluded list or if VST reset has been tried in the DAWs where the plug-in is missing.
 
An alternate method to running a reset is

• moving the plug-in out of the scan path,
• running a manual scan,
• returning the the plug-in back to the scan path and
• running another manual scan.

 
Another method is

• enable the rescan failed plugins in preferences,
• run a manual scan then
• disable the rescan failed plugins option.

 
SONAR Professional may support scan log creation (I have Platinum which does support scan logs). To create a scan log hold the SHIFT key while clicking the scan button. CbB has a checkbox in preferences to create a scan log, The scan logs may help explain what is happening.