I am using ArcGIS 10.1 model builder on windows 8 to create create models for my processes. But when I open the model using Arc GIS 10.1 open model for editing with Arc GIS 10.1 running on Windows 7 it appears not to be editable. I can run the model but I cannot edit it. When I open the model in ArcGIS 10.1 running on windows 7 the model appears as on the screenshot attached below...!Does anyone have an idea what the problem might be Could? I am yet to check if I will have the same problem when I try and edit the model on another windows 8 platform... The model does not use additional tool from extensions like "spatial analyst and so on..." it only uses data management tools. Thank you in advance.