AutoCAD Troubleshooting: Recovering Corrupt AutoCAD Drawing Files
An existing AutoCAD Drawing (.dwg) file will not open, appears to have been corrupted or damaged...
I've experienced this a handful of times over the many years that I have used AutoCAD software. Luckily, it's only a sporadic occurrence, however it does happen from time to time and generally requires a higher level of troubleshooting intervention and effort to resolve.
Corruption of AutoCAD Drawing Files can be introduced in numerous ways.
Some examples are:
- Third-party applications running inside AutoCAD
- DWG files created or saved by non-Autodesk or non-RealDWG products
- AutoCAD terminated while saying the drawing
- Old drawings used repeatedly over long time periods
- Network anomalies (transmission errors, file locking, latent writing of data)
- Storage media degradation (bad sectors on a hard drive)
- Defective or failing RAM
- Operating system issues
- Power surges
- Outdated software
The solutions provided below are primarily sourced from the Autodesk Knowledge Network (CLICK HERE) with my additional suggestions/context added (based on my experience - I have been using AutoCAD software since R12 - 1992).
Drawing File is Not Valid
If this error message (shown below) is displayed on-screen, refer to the Autodesk Knowledge Network: Drawing file is not valid when opening a file in AutoCAD or DWG Trueview.
This error message usually indicates that the drawing has been damaged beyond use causing it to fail to open. Typical causes are hardware malfunction, transmission issues and randsomware encryption.
Drawing Lock Files (.dwl or .dwl2)
Check for and delete the hidden
You may have to turn on 'show hidden files' within Windows Explorer to ensure the .dwl/.dwl2 (and other hidden files by default) are displayed prior to being able to identify and delete, etc.
Once deleted, attempt to open the .dwg file again.
Run RECOVER on the Corrupt/Damaged Drawing File
The RECOVER command attempts to repair then open a damaged drawing file - extracts as much data as it can from the damaged file then opens the file if the drawing file can be salvaged.
Open a blank drawing in AutoCAD and run the RECOVER command. Select the problematic drawing file and AutoCAD will attempt to recover the file. If successful, open the recovered drawing file and validate its contents.
Run RECOVERALL on the Corrupt/Damaged Drawing File
Similar to the RECOVER, the RECOVERALL command attempts to repair a drawing file along with all attached External References (XREFs).
Open a blank drawing in AutoCAD and run the RECOVERALL command. Select the problematic drawing file and AutoCAD will attempt to recover the file. If successful, open the recovered drawing file and validate its contents.
Insert the Corrupt/Damaged Drawing File as a BLOCK
Open a blank drawing in AutoCAD and run the INSERT command. Select the problematic drawing file and if it inserts into the black drawing, attempt to EXPLODE the inserted drawing file. If the explode command is successful, run the AUDIT command. Once complete, run the AUDIT command and repair any identified issues. Save the file and validate its contents.
Recovering from a BAK Drawing File
This is a commonly used approach to salvage a corrupt/damaged drawing file and usually the first option that many users attempt. Navigate to the folder where the problematic drawing file is stored and locate the
Note: the BAK file is created automatically when the DWG file is saved (the previous DWG file status is duplicated as a BAK file, based on the latest save).
Recovering from an Autosave File (.SV$)
For more information on Autosave, refer to a previous theCADcafé blog post - CLICK HERE.
The AutoSave feature creates a backup of the currently open drawing to a folder on the computers local hard drive. The file has the extension .SV$ and can be renamed to .DWG to recover a drawing. It is important to note that there is only 1 AutoSave file and it is overwritten each time a different drawing is opened. The Autosave feature can be turned off so don't rely on it being available.
Try Opening the Corrupt/Damaged Drawing File in DWG Trueview
You can attempt to convert the problematic drawing file to an earlier DWG File Format Version, then try to open the converted file.
Windows (IT) Nightly Backups, etc.
Depending on the company's IT department and their available contingency/data management systems, determine if a backup can be salvaged from an earlier date (when the problematic drawing file was last functioning correctly).
Use AutoCAD Map 3D to Query the Corrupt/Damaged Drawing File
I have had success in salvaging an otherwise completely corrupted/damaged drawing file, using the query functionality within AutoCAD Map 3D. I haven't attempted this type of fix for a few years now, however it may still be a valid option if all else fails.
AutoCAD Map 3D DRAW MODE retrieves drawing objects from attached drawings and copies them into the current drawing. This functionality can be used to potentially salvage data from a problematic drawing.
Run a map query to attempt to extract information out of the problematic drawing. Within Display Manager (MAPWSPACE command) click Data -> Add Drawing Data -> Attach Source Drawings.
Within the Define/Modify Drawing Set dialog box, click ATTACH and navigate to the folder where the problematic drawing file is stored, select ADD and click OK.
Next, click Home -> Data -> Define Query and within the Define Query of Attached Drawings dialog box, under Query Type, click Property. Under Property Type, click Object Type -> Values and select all the required objects/entities.
Under Query Mode, click Draw and click OK, then view the output.