If you have v8 you need to be sure you have permission to modify the Plugins folder - without that changes made with the Plugins Manager will NOT be retained on a restart of SketchUp - see this... http://sketchucation.com/resources/tutorials/intermediate/811-setting-security-permissions-in-sketchup Also see this on generally installing Plugins... http://sketchucation.com/resources/tutorials/beginner/108-installing-sketchup-plugins and this on the PluginStore tools... http://sketchucation.com/resources/plugin-store-download which has sections on the Plugins Manager - you are NOT Uninstalling them - you are Disabling them.