have you uninstalled a previous version of Sonar? I removed 8.5 and bitbridge was deleted with it so i was getting a missing plugin message also. do you have x1 looking in the right folders for your plugins?

I wonder if. X1 is not searching in the right directory for plugs? Go into Preferences and click vst settings in the left-hand column of the window. You'll then see, among other things, a list of all the directories Sonar will search in for your vst plug-ins. Add the missing ones and re-scan. Then reload your project and hopefully all will be well.