Hi, No internet connection is required to run Tekla BIMsight so it's possible to work with Tekla BIMsight also in an offline mode. Tekla BIMsight can be started ten times without registering, and after ten starts each user need to register their copy of Tekla BIMsight. When registering an online connection is required to access www.teklabimsight.com server. After registration, which is free of charge, you can continue working in an offline mode. However, to view the Help Center content, such as Help documentation or Support Forum you need to be online. Thanks, Heikki