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TrustedDWG: Exploring the Features and Benefits of AutoCAD

Frank Mayfield
January 12, 2018

TrustedDWG is a key function of AutoCAD and AutoCAD LT that analyzes DWG files as they are being opened. The function checks to see if the DWG file was last saved with an Autodesk product or by a software developer who is licensed to use the RealDWG toolkit. If the file does not pass the TrustedDWG analysis, it will inform you in various ways that the DWG file may not be compatible, nor guarantee its integrity when used with AutoCAD or AutoCAD LT. So, let’s take a look at how to get the most out of this core benefit.

How AutoCAD or AutoCAD LT Alerts You

The visibility of these warnings is controlled by the DWGCHECK system variable. DWGCHECK is an integer variable, and is saved in the registry — not each drawing. By default, DWGCHECK is set to 1. There are 8 different states that can be set and which determine what type of alert is or isn’t displayed. We’ll be looking at the alerts that you’ll see in the default setting of 1.

First, upon opening a DWG file that was last saved from a non-Autodesk product, you’ll get the following dialog box:

AutoCAD TrustedDWG

You’ll have the opportunity to open the file or to cancel. If you choose to check the “Always open DWG files” option, it will not change the setting of DWGCHECK, but instead, will simply hide this dialog box. You can change this setting (or any hidden message) via the Settings tab in the Options dialog box.

AutoCAD TrustedDWG

Important Note: Once a non-Autodesk DWG is opened and then SAVED, it will then pass the TrustedDWG test function, so it’s always a good idea to check the drawing carefully for any missing entities or data before saving.

Additional Alerts

In addition to the alert message, the AutoCAD command line will also warn you of a non-compliant DWG file. While opening, one of the following messages will appear:

AutoCAD TrustedDWG

The top message alerts you that the DWG file did not pass the TrustedDWG test. The bottom message will display if it finds that it was last saved by an Autodesk product.

If you choose to open a DWG file that doesn’t pass TrustedDWG, you will also see a warning icon in the system tray of AutoCAD or AutoCAD LT. Hovering over the icon will display the warning seen below. It is yet another visual reminder to carefully check the contents of the DWG file before saving, in order to ensure its integrity.

AutoCAD TrustedDWG

More on TrustedDWG

About Opening Drawings

What is a DWG?

What is TrustedDWG?

The DWGCHECK system variable


Keep Exploring

Want to learn more? Check out all the benefits of AutoCAD on our Features page; troubleshoot and get the details on previous software versions over on the Autodesk Knowledge Network; or take a look at all entries in our series, Exploring the Features and Benefits of AutoCAD.



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Frank Mayfield

I have worked with AutoCAD and Autodesk software since 1984 v 2.62. I have been involved with various industries over the years, ranging from design of switchgear and panels for U.S. Navy ships, to simulated instruments for flight simulators, oil and gas piping, offshore oil rig equipment, AEC and MEP design and CAD management, and currently run my own CAD Management consulting firm. I was most recently the CAD Administrator for the Oil, Gas and Chemical division at Benham, a Haskell Company. In that role, I oversaw all aspects of the AutoCAD, CADWorx, Plant3D and AutoPlant environments. I am a Certified Professional in AutoCAD 2015 lic no. 00382470, I volunteer with AUGI as the AutoCAD Gallery Manager, and am a member of the AutoCAD Customer Council, the Product Delivery Customer Council, the Autodesk Advisers Community, and the Autodesk User Panel. As a top rated mentor for in-trial users of AutoCAD 2018 and AutoCAD LT 2018, I have provided guidance and answered questions for over 2,500 new users in more than 50 countries worldwide.