Try these solutions in order from simplest to most advanced. None require paid software.
The file AcIsmObj20.dbx is a legitimate, built-in Autodesk component. It is the file, which handles raster images and certain 3D object data within the software.
Your antivirus may quarantine acismobj20.dbx thinking it's a threat. autocad fatal error acismobj20dbx free
In the Autodesk setup wizard page that appears, select .
Locate your version of AutoCAD in the list, right-click it, and select . Try these solutions in order from simplest to most advanced
Permissions issues can prevent AutoCAD from reading necessary library files upon startup. Right-click the AutoCAD desktop icon. Select . Go to the Compatibility tab. Check Run this program as an administrator . Click Apply and OK . 5. Remove Corrupted Drawings / Clean 3D Data
Below is a structured troubleshooting guide, progressing from simple to more complex solutions. Follow these steps in order until the issue is resolved. It is the file, which handles raster images
Use the (free from Microsoft) to remove all Autodesk entries cleanly, then reinstall from your Autodesk Account.
If the error persists across all files, the acismobj20dbx file itself might be damaged. Go to > Programs and Features . Select Autodesk AutoCAD . Click Uninstall/Change . Choose Repair or Reinstall when prompted 1.2.4. Proactive Tips to Prevent Future Errors