Sonar is throwing up a weird fault again , i had this happen before , i basically added a drum bus effect and then the next day it tells me the drum bus effect is no longer available.
nothing has been removed on my pc , i am using the latest version of Soanr ,all upto date and everything.
 
Why is it doing this  ?
 
 

https://ibb.co/f5KEKF

I've had synths go missing, its like sonar is skipping them when it scans for them on startup. Restarting or rescanning seems to fix it.
Was thinking maybe if I turned off scan for vsts on startup it might be a way round this annoying problem.

Hi. Does this happen with any particular plugin/synth, or several?
All the best.
Edit: Didn't see the picture first.
 

If you used CCC to install, try re install the Engineering Suite and see if that helps.
If not download it from your Cakewalk account, and re install it as normal.

This may fall under the superstition category, but I find that after updates - either Windows or sometimes SONAR - I need to do a VST reset and rescan. That seems to solve all kinds of plug-in related issues should they crop up.