If you encounter issues where VST instruments are opening as a Sampler Channel and not responding to input they are probably missclassified as Effects plugins. The Channel Rack hosts Generator (instrument) plugins, to avoid these Generator plugins from opening as Effects in the Mixer you must do the following:
After the scan is completed, your plugins should now be properly identified as Generators and should no longer open as Effects plugins.
Alternative solution
If the above solution doesn't work you may need to remove associated plugin database entries containing old information about the plugin(s):
If the plugin opens correctly you can now manage the plugin using the Plugin Manager or 'More plugins...' window as usual. If the issue persists, please create a thread on our Technical Support forum where we'll be able to assist you further.
Image-Line Support Team