3 steps to open file with DEF extension
Usually solving problems with DEF file is simple – just install proper software and open the file. Read the guide and open DEF file now!
DEF File Extension
- File type Module-Definition Format
- File developer N/A
- File category Developer Files
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File popularity rating
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What is a(n) DEF file?
DEF is a short for Module-Definition File, which is used by linkers and binders to tell the linker/binder where the definitions of DLLs and executables are located. In general, DEF files contain information related to a module’s name, version, and various exported and imported symbols. It can also be used to export functions from a Windows DLL and create valid symbols in EXE files.
DEF files are plain text files which usually have a .def extension. The main sections of DEF files include the DESCRIPTION, EXPORTS, IMPORTS and VERSIONINFO sections. The file contents adhere to the standard name=value or directive=value notation.
How to open DEF file?
There could be multiple reasons for which the system does not support given file. In the case of DEF extension, it is probable that none of the installed programs support given file type. Therefore, user should undertake the following steps
Step 1: Install a program that supports DEF files
If an application that supports DEF files is installed on user’s system, but is not used to open such files by default, right-click on the file icon and choose "Open with" option from the menu. Next, select the proper application and check the "Always use the selected application to open this kind of files" box. The system will store this information in its registry and use the selected program to open files with DEF extension by default.
Hint for Mac OS users
For Mac OS users the procedure is analogous – open the file menu by right-clicking on the DEF file and choose "Information" option and select "Open with program" option. From the submenu select an application and click on "Change all" button.
Step 2: Find and download proper software
Inability to open DEF files may also be related to the lack of any application that supports given file being installed on the system. Should that be the case, user needs to download and install one of the following applications. Once installed, the system will automatically associate newly installed application with DEF files. If this step fails, see step 1.
Programs that support files with DEF extension
Step 3: Check the DEF file for errors
Sometimes, although relatively rarely, steps 1 and 2 might not lead to expected results. There can be several reasons for such situation to occur:
- DEF file has been downloaded from the internet but for some reason it is incomplete. In such case the file should be re-downloaded and opened again.
- Structure of given DEF file could be corrupted and as such the program is not able to open the file
- Storage medium on which the file was stored is damaged
- It is important to ascertain that the icon representing given file is not a shortcut a related DEF file no longer present in the location to which the shortcut points
- If the user account has restricted access privileges it is advised to contact the system administrator or an IT expert
