How to Recover Deleted
DWG / CAD Files on Windows

For engineers, architects, and designers, a deleted DWG file isn't just lost data — it can mean days of redrawing, missed project deadlines, and client friction. AutoCAD DWG files are often the single most valuable digital asset in an engineering workflow, representing hundreds of hours of precision work.

The good news: DWG files are highly recoverable. Their proprietary binary format has a consistent, identifiable file signature that allows tools like HDH DataRecovery to locate and reconstruct them even from formatted drives or corrupted storage media. This guide covers exactly how to do it.

1. Why Engineers and Architects Lose DWG Files

2. Understanding DWG File Signatures

DWG is AutoDesk's native binary format for AutoCAD drawings. Every DWG file begins with a version identifier in the first 6 bytes — for example:

HDH DataRecovery's deep scan engine knows all of these DWG version signatures and searches for them during file carving. When a matching header is found on a disk sector, the tool reads the file's internal structure to determine its exact length and extract the complete drawing. This works whether the drive has been formatted, the file system is corrupted, or the file was deleted normally.

3. Step-by-Step DWG File Recovery

1. Stop Using the Affected Drive Immediately Close AutoCAD and any other applications writing to the drive. Do not save new files or run AutoCAD's autosave on the affected drive. Every write risks overwriting your deleted DWG sectors.
2. Check AutoCAD's Automatic Backup First Before running recovery software, check whether AutoCAD saved a backup. AutoCAD automatically creates .BAK files (same location as the DWG, same name with .bak extension). Also check the autosave folder at: C:\Users\[Username]\AppData\Local\Temp\ — AutoCAD saves .sv$ autosave files here. Rename .sv$ to .dwg to open them.
3. Install HDH DataRecovery on a Different Drive Download and install HDH DataRecovery on your system drive or a USB — not on the drive containing the deleted DWG files. This prevents overwriting the file data you want to recover.
4. Select the Drive and Run Deep Scan Open HDH DataRecovery and select the drive where the DWG files were stored. Choose Deep Scan to activate DWG signature-based file carving. If your CAD files were on an external drive or USB, connect it before launching the scan.
5. Filter Results by DWG / DXF After scanning completes, filter the recovered file list by extension (DWG, DXF). HDH DataRecovery shows DWG file size and version to help you identify the correct file. Larger DWG files with complex assemblies will be several MB to tens of MB in size.
6. Recover to a Separate Location Save recovered DWG files to a different drive. Do not save to the source drive. After recovery, open the DWG in AutoCAD or the free AutoCAD DWG TrueView to verify the drawing is intact.

4. DWG Recovery Tips for CAD Users

Enable AutoCAD's built-in backup features before the next project

AutoCAD has several built-in safeguards that most users leave at defaults. After recovering your files, configure these settings to prevent future loss:

• Automatic Backup (.BAK): Options → Open and Save → Create Backup Copy with Each Save. This creates a .BAK file every time you save, preserving the previous version.
• Autosave Interval: Options → Open and Save → Automatic Save → set to 5–10 minutes. AutoCAD saves a recovery copy to the temp folder at this interval.
• Autosave Location: You can set a custom autosave folder. Point it to a cloud-synced folder for offsite backup.

Use versioned file naming

Save DWG files with version suffixes: ProjectA_foundation_v01.dwg, v02.dwg, etc. This prevents accidentally overwriting a good version and gives you a revision history without needing a full version control system.

Keep a weekly external backup

Copy active project DWG files to an external HDD or NAS weekly. Engineering firms with global offices often have large DWG libraries — a simple scheduled robocopy job can automate this. HDDs are cheap; redrawing a mechanical assembly is not.

5. Supported CAD and Technical File Formats