Understanding BAK files in AutoCAD is essential for any CAD professional. These backup files are automatically generated by AutoCAD every 10 minutes during your drawing sessions. They serve as safety copies of your work, stored in the same directory as your original DWG files.
What Are AutoCAD BAK Files?
A BAK file is an automatic backup copy of your previous drawing save. When you save a drawing, AutoCAD renames the existing DWG file with a .BAK extension and creates a new DWG file with your latest changes. By default, these files are stored in your drawing’s working directory at:
- Windows:
C:\Users\[Username]\Documents\AutoCAD [Version]\[Drawing Location] - Mac:
/Users/[Username]/Documents/AutoCAD [Version]/[Drawing Location]
Common Causes of BAK File Issues
Several factors can prevent access to BAK files:
- File Permission Restrictions: Insufficient access rights to the backup directory
- File Corruption: Data integrity issues during saving
- Software Conflicts: Interference from antivirus or system optimization tools
- Version Incompatibility: BAK files created in newer AutoCAD versions
- Storage Issues: Insufficient disk space during backup creation
Opening BAK Files: Step-by-Step Solutions
1. Basic File Extension Change
- Locate your BAK file in File Explorer
- Right-click and select “Rename”
- Change “.bak” to “.dwg”
- Press Enter
- Open the file in AutoCAD
2. File Association Setup
- Right-click the BAK file
- Select “Open with” → “Choose another app”
- Mark “Always use this app”
- Select AutoCAD from available programs
- If needed, browse to
C:\Program Files\Autodesk\AutoCAD [version]\acad.exe
3. Drawing Recovery Methods
Basic Recovery:
- Launch AutoCAD
- Type “RECOVER” in the command line
- Select your converted BAK file
- Wait for the repair process
Advanced Recovery:
- Use the “AUDIT” command for detailed file checking
- Try “DRAWFIX” for severe corruption cases
- Enable drawing recovery logs through Options menu
4. Autosave File Recovery
- Search for SV$ files in your drawing folder
- Rename from “.sv$” to “.dwg”
- Open in AutoCAD
- Review and save any recoverable content
Advanced Recovery Techniques
Drawing Repair Tools
- ScriptPro: Batch processes multiple corrupted files
- Drawing Recovery Manager: Access through File menu
- Partial Open: Loads only selected objects
- ObjectARX: Recovers specific object data
External Recovery Options
- DWG TrueView: Free viewer for BAK files
- AutoCAD Design Review: Alternative viewing solution
- Third-party recovery tools: For severe corruption cases
Prevention Strategies
Optimal Backup Configuration
- Set AutoSave interval to 5-10 minutes
- Enable Incremental Save Percentage: 50% recommended
- Use Sheet Set Manager for project organization
- Implement External References management
Best Practices
- Regular manual saves (CTRL+S)
- Maintain adequate free disk space
- Close drawings properly
- Use eTransmit for file packaging
- Create manual backups for critical projects
System Compatibility
Supported Environments
- AutoCAD Versions: 2016-2024
- Operating Systems:
- Windows 10/11 (64-bit)
- macOS Monterey or later
- Hardware Requirements:
- 8GB RAM minimum
- 6GB free disk space
- 64-bit processor
Known Limitations
- Maximum BAK file size: 2GB
- Recovery success rate depends on corruption level
- Version compatibility issues between releases
- Network location restrictions
- Limited cloud storage support
Additional Tools and Resources
Built-in Utilities
- Drawing Recovery Manager
- Batch Drawing Recovery
- Reference Manager
- Drawing Status Monitor
Workspace Setup
- Enable file extensions view
- Configure backup locations
- Set up recovery folders
- Monitor autosave settings
Remember to maintain regular backups beyond relying on BAK files alone, as they should be considered a last resort recovery option rather than a primary backup solution.
