Hi Jerome, there can be many reasons why this file does not open. Vista is not a supported plattform for IsoView yet. Before taking other OS issues on supported plattforms in consideration you can check this: First of all it can be a CGM file that IsoView 5 "does not know" (E.g.: I believe IsoView 5 does know how to handle S1000D CGMs). Hence I recommend to check if IsoView 5 refuses to open all CGM flavors. IE handles the IsoView CGM connection with a so called MIME type, you may check if there is something wrong. You can give the IsoView 7 Evaluation Kit a try as well. If it works with that, it is worth to consider an upgrade to the most recent version of IsoView (currently version 7.0, IsoView 5 was released around 2001). regards, Christian