MDL File Extension

What is MDL file?

MDL files store 3D models of aircraft used in Microsoft Flight Simulator computer games.

What are the contents of an MDL file?

MDL files store different data depending on which version of Flight Simulator they are used. Older MDL files used DLL libraries to store w aircraft models. They were saved in binary format, but did not contain executable code. The models were only accessible after MDL files were loaded by MS Flight Simulator.

How is data stored in newer versions of MDL format?

Since Flight Simulator 2002, each next iteration uses MDL files that store data based on RIFF format (data is organized in well-defined sections). The following is the list of various MDL implementations:

• MDL8,
• MDL9,
• MDLX.

Each implementation is used by FS2002, FS9, and FSX, respectively. FS9 supported both MDL9 (environment models) and MDL8 (aircraft models). MDLX was a completely new implementation of MDL format.

Programs which support MDL file extension

Below is a table that list programs that support MDL files. Files with MDL suffix can be copied to any mobile device or system platform, but it may not be possible to open them properly on target system.

Updated: 04/07/2023

How to open file with MDL extension?

There can be multiple causes why you have problems with opening MDL files on given system. On the bright side, the most encountered issues pertaining to Flight Simulator 95/98 3D Model Format files aren’t complex. In most cases they can be addressed swiftly and effectively without assistance from a specialist. We have prepared a listing of which will help you resolve your problems with MDL files.

Step 1. Install MDL2DXF software

The most common reason for such problems is the lack of proper applications that supports MDL files installed on the system. This one is an easy one. Select MDL2DXF or one of the recommended programs (for example, Microsoft Flight Simulator 95, Microsoft Flight Simulator 98) and download it from appropriate source and install on your system. The full list of programs grouped by operating systems can be found above. If you want to download MDL2DXF installer in the most secured manner, we suggest you visit Henry Väppling website and download from their official repositories.

Step 2. Verify the you have the latest version of MDL2DXF

If the problems with opening MDL files still occur even after installing MDL2DXF, it is possible that you have an outdated version of the software. Check the developer’s website whether a newer version of MDL2DXF is available. It may also happen that software creators by updating their applications add compatibility with other, newer file formats. This can be one of the causes why MDL files are not compatible with MDL2DXF. The most recent version of MDL2DXF is backward compatible and can handle file formats supported by older versions of the software.

Step 3. Set the default application to open MDL files to MDL2DXF

After installing MDL2DXF (the most recent version) make sure that it is set as the default application to open MDL files. The next step should pose no problems. The procedure is straightforward and largely system-independent

The procedure to change the default program in Windows

• Clicking the MDL with right mouse button will bring a menu from which you should select the Open with option
• Click Choose another app and then select More apps option
• To finalize the process, select Look for another app on this PC entry and using the file explorer select the MDL2DXF installation folder. Confirm by checking Always use this app to open MDL files box and clicking OK button.

The procedure to change the default program in Mac OS

• From the drop-down menu, accessed by clicking the file with MDL extension, select Information
• Find the Open with option – click the title if its hidden
• Select MDL2DXF and click Change for all...
• Finally, a This change will be applied to all files with MDL extension message should pop-up. Click Continue button in order to confirm your choice.

Step 4. Ensure that the MDL file is complete and free of errors

If you followed the instructions form the previous steps yet the issue is still not solved, you should verify the MDL file in question. It is probable that the file is corrupted and thus cannot be accessed.

1. The MDL may be infected with malware – make sure to scan it with an antivirus tool.

If the file is infected, the malware that resides in the MDL file hinders attempts to open it. Scan the MDL file as well as your computer for malware or viruses. MDL file is infected with malware? Follow the steps suggested by your antivirus software.

2. Verify that the MDL file’s structure is intact

If the MDL file was sent to you by someone else, ask this person to resend the file to you. It is possible that the file has not been properly copied to a data storage and is incomplete and therefore cannot be opened. It could happen the the download process of file with MDL extension was interrupted and the file data is defective. Download the file again from the same source.

3. Check if the user that you are logged as has administrative privileges.

Some files require elevated access rights to open them. Switch to an account that has required privileges and try opening the Flight Simulator 95/98 3D Model Format file again.

4. Check whether your system can handle MDL2DXF

If the system is under havy load, it may not be able to handle the program that you use to open files with MDL extension. In this case close the other applications.

5. Ensure that you have the latest drivers and system updates and patches installed

Regularly updated system, drivers, and programs keep your computer secure. This may also prevent problems with Flight Simulator 95/98 3D Model Format files. It is possible that one of the available system or driver updates may solve the problems with MDL files affecting older versions of given software.

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