CADDManager on May 9th, 2007

From the Readme…
Opening an old file in ACA 2008 can appear to hang up your system.
When previous version drawings are opened, a dialog is displayed with a warning that saving this drawing will upgrade AEC objects to 2007 format. If a previous version drawing is opened by double-clicking the file in Windows [...]

Continue reading about AutoCAD Architecture 2008 - Hang Time