On August 23, 2010, Autodesk released Update 1 for AutoCAD 2011. Unfortunately, Update 1 introduced an issue when conducting certain operations that may cause AutoCAD to shut down. This issue affects a small number of users.
We have removed Update 1 and will reintroduce it in the near future when the issue has been resolved. For customers who have already installed Update 1, a Hotfix will be posted shortly. Please be assured that Autodesk is wholly committed to the quality of AutoCAD, and regrets this error.