alphabetical list of extensions

File extension .DEF

Description of the problem

If you have on your computer a .DEF file that you cannot open, you are in exactly the same situation as thousands of other people who have similar problems with this or any other unknown file.

There may be several reasons why you cannot open the file with .DEF extension. Directly on this website you can find a solution of the most common problem with the .DEF file – that you do not have on your computer the appropriate program to open the file.

Solution

From the list below, select the appropriate program, install it and double click on the icon of a file that did not want to open - the problem with the .DEF file extension should be solved. However, if this does not happen, go back to the website to learn about other possible causes of the error, which have been described at the bottom of the website.

Category

Developer Files

Developer

N/A

Popularity

File name: Module-Definition File

Programs that will open this file:

Windows

AniSprite

ArcGIS for Desktop Basic (ArcView)

AutoCAD

SmartWare

SmartWare II

Visual C++

Visual Studio

Linux

DataFlex

Category

Spreadsheet Files

Developer

SmartWare

Popularity

File name: SmartWare II Data File

Programs that will open this file:

Windows

SmartWare

Category

Game Files

Developer

Elecbyte

Popularity

File name: M.U.G.E.N. Character Definition File

Programs that will open this file:

Windows

M.U.G.E.N.

Category

Data Files

Developer

IObit

Popularity

File name: IOBit Malware Fighter Definitions File

Programs that will open this file:

Windows

Malware Fighter

Remember!

The .DEF file extension can correspond to several not related file formats. If there is more than one file format with the .DEF extension, you will probably find most of them at this website. Remember that you need to download a program to support a particular file type. So first look through the entire contents of the website to select a program to support just the file you have.

Other possible reasons why your .DEF file does not want to open

In addition to the problem described above, i.e. the lack of the appropriate application to support the .DEF file, there may be several reasons that cause problems with opening and operation of the data format:

1. Incorrect version of the installed application

A quite common problem is the lack of application in the appropriate version. Even if you have an application, with the help of which you should open the .DEF file, you may have a problem with it because of its version. Perhaps in previous versions the application has not yet supported the .DEF file, so download the update and check again.

2. Incorrect .DEF file association with the program

If you have already installed the appropriate application, and it is the correct version, the file may not open correctly, because the operating system does not have information that this program supports the file. So you need to "show" which program the computer should use. To do this:

Right-click the .DEF file
Go to the "Open with" - then "Choose default program ..."
Locate the appropriate application
Click "OK"

3. The file is corrupt

It also happens that the file you want to open is corrupt and therefore there is no such possibility. In this situation, you should find its different version, or ask a person from whom you got, to send it again.