drummaman: You always need to update all of the plugins. The uninstaller of V11 make sure there won't be plugins left. I'd recommend installing V12 again, make sure all the VST/VST3... interfaces are enabled (which is default), perform plugin cleanup, just in case, then select the plugins you want to install. Make sure the plugin paths are correct (only VST2, all other interface have predefined paths by standard, I wish the same was for the poor old VST2...
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