How to repair corrupt AutoCAD files

 Issue:

How to repair a damaged or corrupted AutoCAD drawing (.dwg) file. A drawing may have one or more of the following symptoms: 

• Drawing file does not open. 
• Drawing file opens with errors. 
• File hangs or crashes AutoCAD. 
• Slow performance when editing a file. 
• Error messages appear when working in a file. 
• Commands do not work or are delayed. 
• Unexplained increase in file size.  
• Display or regen problems. 
• Drawing elements missing or shown incorrectly. 
• Recovered version of the drawing opens but is blank.

Causes:

• Third-party software is running within AutoCAD. 
• Non-Autodesk or non-RealDWG product created or saved the file.
• AutoCAD terminated while saving a drawing file, such as during a power surge or outage. 
• Old drawings have been used repeatedly over a long time period. 
• Network anomalies have occurred (such as transmission errors, file locking, and latent writing of data). 
• Storage media has degraded (such as bad sectors on a hard drive).
• System RAM is failing or defective.
• Operating system issues exist.

Solution:

Follow this troubleshooting guide "How to repair corrupt AutoCAD drawings" .

Work through the following solutions as listed:

• If a drawing file will open, see Optimizing the AutoCAD drawing file: Purge, Audit & Recover.
• If a file will not open, see Recovering drawing files which fail to open in AutoCAD.
• Follow the copy/paste operations in Optimizing the AutoCAD drawing file: Windows Clipboard Copy and Paste.
• Export the file using the WBLOCK command (see Optimizing the AutoCAD drawing file: Wblock Purge).
• Remove duplicate or overlapping objects in the drawing with the OVERKILL command (see Using OVERKILL to remove duplicate or overlapping objects in AutoCAD).
• Remove excessive constraints in the drawing using the DELCONSTRAINT command (see How to turn off and delete constraints in AutoCAD).
• Resolve issues selecting or modifying 3D solids and surfaces with the BREP command (not available in AutoCAD LT) (see 3D objects display wrong, shift position, offset from grips, or move in AutoCAD).
• Remove excessive annotation scales from the drawing with the SCALELISTEDIT command (see Warning: "This drawing contains a large number of annotation scales" when opening a file in AutoCAD).
• Remove excessive layer filters with the FILTERS command (see How to delete layer filters in AutoCAD).