Today’s good question comes from James. He asked why multiple sessions of AutoCAD 2008 are launched when opening drawings from Explorer. You would expect this behavior if the SDI variable is set to 1 (Single Document Interface) but when it’s set to 0 (as it is by default) you expect multiple drawings to open in a single session of AutoCAD. This was a problem with AutoCAD 2008 but it was fixed in the AutoCAD 2008 Service Pack 1. You can download the service pack from the Autodesk Website.
Thanks to James for his good question! By the way, this problem does not exist in AutoCAD 2009.