To enable or disable the TIFF Viewer Browser Plug-In, run the TIFF Viewer as an Administrator, and go to File > Options.
In TIFF Viewer Options, please navigate to the Browser Plug-in tab. One can enable the Browser Plug-in by selecting the desired file types which should be associated with the TIFF Viewer Browser Plug-in.
Click on the OK button to save changes.
To read more about Browser Plug-in Settings, please refer to the Browser Plug-in section of the manual.