Issue:
When the icon for all AutoCAD .dwg files is blank, it's not clear what CAD application will open the drawing when it's double-clicked.
Also, double-clicking on a second blank dwg icon may open a second instance of the AutoCAD version instead of opening in that same instance.
Causes:
On a new workstation, the installer for AutoCAD was partially blocked from setting the file association for .dwg files and for how a second instance responds.
Also, the standard solutions listed below for both issues don't always work reliably or they are too complicated to complete successfully.
- DWG file type associativity in Windows for AutoCAD
- Double-clicking or opening a DWG file starts a new instance of AutoCAD product
Solution:
Another proven solution that is easier is when a second workstation is available with the same Windows version that has AutoCAD dwg icons shown correctly and double-clicking a second icon opens the drawing in the same AutoCAD session. It's even better if both machines have the same CAD applications installed.
The working machine can be used as a donor for exporting the registry key that stores the file association for .dwg files. Once exported and copied to the problem machine, the .reg file that was exported can be double-clicked to overwrite the same registry key that has the wrong behavior.
The registry key is here:
Computer\HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.dwg
Copy the .reg file to the problem machine and either double-click and confirm or right-click and click Merge, then confirm the registry update.
With the transplanted .dwg registry key, the icons should appear correctly and a second dwg should open in the same session of AutoCAD that is open.
Warning! Problems caused by improperly editing the Windows registry could render your computer operating system unusable. Microsoft provides a wealth of critical information that you need to know about the registry, here in the Microsoft Knowledge Base.
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