After entering the OPEN command in AutoCAD, either through the File menu, the application menu, or via the command line, the Select File dialog window takes a long time to appear.
Once the Select File dialog appears, check the shortcuts in the Places area on the left of the window. Invalid shortcuts here will cause a delay as the dialog opens while AutoCAD attempts to resolve the non-existent locations. If you are having trouble getting the Select File window to appear at all, try resetting AutoCAD to defaults (see How to reset AutoCAD to defaults).
Another possible solution is to turn off the digital signature icons for files:
- On the keyboard, hold down the WINDOWS key and then hit R.
- In the Run window, type ACSIGNOPT and then click OK.
- In the window that comes up, uncheck "Validate digital signatures and display special icons."
- Click OK.