What is the DWL file format?
.dwl files are lock files created by AutoCAD and TurboCAD - professional software for 2D and 3D CAD design - and each one functions as a blocking file. It is generated when a target drawing (such as a .DWG or .TCW file) is opened within the program, preventing simultaneous access by other users.
A .dwl blocking file is created in order to protect against concurrent access to the parent drawing by more than one person at the same time, which would risk corrupting it. Users can still open and view the drawing; the blockade applies specifically to introducing modifications while another session holds the lock. AutoCAD also creates a companion .DWL2 file alongside .dwl; both lock files must be absent before the drawing is considered truly unlocked.
A .dwl file is created temporarily and deleted automatically after the project is closed. However, it is possible that the file will not be deleted - for instance, in the case of a power failure or sudden device shutdown. Moreover, .dwl files are often not automatically deleted after a program crash. In such cases, they should be deleted manually before attempting to reopen the drawing.
A user may open a .dwl file with a plain text editor such as Notepad. Its content includes the user name, computer name, timestamp, and the name of the locked drawing file - information used for initializing and releasing the lock on the project.
Security & safety
RISK: LOWA DWL is a harmless few-line text file and cannot carry executable content, so it is not a malware concern. The only practical caution is operational: do NOT delete a .dwl/.dwl2 while the associated drawing is actually open by someone (especially on a shared network drive) - the lock is what stops two people overwriting each other's edits. If a lock is stale after a crash, confirm nobody has the drawing open, then delete the .dwl/.dwl2 to release it. Normal closing of the drawing removes the lock automatically.
Format details
in a nutshellPrograms that open DWL files
Windows3 apps
TurboCAD
Paid Open the matching .tcw drawing, not the .dwl. TurboCAD manages the lock for its drawings the same way. 
AutoCAD
Paid Don't open the .dwl - open the matching .dwg. AutoCAD creates and removes the lock automatically; a stale .dwl can be deleted to free the drawing. 
Notepad (built-in)
Built-in If you're curious, open the tiny .dwl in Notepad to see the user/computer/time that holds the lock. There is nothing else inside. Technical details
deep spec| Format type | Plain-text lock file (not a CAD drawing) |
| MIME type | text/plain |
| File size | Typically under 1 KB |
| Character encoding | ASCII / UTF-8 |
| File signature | None - no fixed magic bytes or header |
| Associated drawing format | .DWG (AutoCAD), .TCW (TurboCAD) |
| Companion lock file | .DWL2 - AutoCAD creates .dwl and .dwl2 together for each open drawing |
| Typical lifespan | Temporary; deleted automatically on normal program exit |
| Stored fields | Username, computer name, lock timestamp, drawing file name/path |
| Applications | AutoCAD (Autodesk), TurboCAD (IMSI/Design) |
| Platform | Windows (primary); AutoCAD also runs on macOS |
| Purpose | Exclusive write-lock - prevents concurrent edits to the parent drawing |
| Manual removal needed | Yes - if the program crashes or loses power, stale .dwl files must be deleted by hand |
| Readable with | Any plain-text editor (e.g., Notepad) |
| Released | Used by AutoCAD (and TurboCAD) for multi-user file locking |
| Specification | www.autodesk.com |
DWL conversions
Community Q&A
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