DEF File - opening and understanding

Did your computer fail to open a DEF file? We explain what they are used for and recommend software that we know can open or otherwise handle your .DEF files.

What is a DEF file?

Files that contain the .def file extension are most commonly associated with Microsoft Visual C++ definition files. These files list the exports and attributes of a specific program that is linked by an application linker.

The DEF file format is commonly used when creating a dynamic link library during the development of a software application.

The 3D Fassade Plus software application also uses the .def file extension. These DEF files contain definition module files that are used by the software.

A variety of Nova Logic software games also use files with the .def file suffix. These DEF files contain game weapon files that are referenced by the software during a user's gameplay.

How to open DEF files

You will need a program compatible with the specific file you are trying to open, as different programs may use files with file extension DEF for different purposes.

While we have not verified the apps ourselves yet, our users have suggested 10 different DEF openers which you will find listed below.

Suggest another file format using extension DEF

While we know of one file format using the .DEF file extension, there may be more. It is widespread that different programs use files with the same file extension for very different types of data. Please let us know if you are aware of a different kind of .DEF file.

Various viewers for this file format

These apps are known to open certain types of DEF files. Remember, different programs may use DEF files for different purposes, so you may need to try out a few of them to be able to open your specific file.

Stuffit ExpanderStuffit ExpanderUser submitted
Army BuilderArmy BuilderUser submitted
Any Video Converter ProfessionalAny Video Converter ProfessionalUser submitted
Microsoft Visual Studio .NETMicrosoft Visual Studio .NETUser submitted
progeCAD ProfessionalprogeCAD ProfessionalUser submitted
Movie Magic ScreenwriterMovie Magic ScreenwriterUser submitted
Flash Movie PlayerFlash Movie PlayerUser submitted
WinEdtWinEdtUser submitted
progeCAD Professional EnglishprogeCAD Professional EnglishUser submitted
TimetableTimetableUser submitted
We have not verified any software that we know for certain will work with DEF-files on Mac. If you know one, please use the 'Suggest a program' link below and tell us about it!
We have not verified any web services that we know for certain will work with DEF-files. If you know one, please use the 'Suggest a program' link below and tell us about it!