DEFS file format description

Many people often share .defs files without providing instructions on how to use them. This can make it difficult for users to determine which program is compatible for editing, converting, or printing .defs files. To address this issue, we have created this page to offer assistance and guidance on handling .defs files. We provide information on compatible software, editing instructions and conversion options to help users effectively interact with .defs files.

Our aim is to simplify the process and promote seamless use of the .defs file format.

2 filename extension(s) found in our database.

.defs - BlueJ Settings File

The DEFS development files are related to BlueJ. The DEFS file is a BlueJ Settings File. BlueJ is an integrated development environment (IDE) for the Java programming language, developed mainly for educational purposes, but also suitable for small-scale software development.

Development files
- / -
BlueJ Settings File related extensions:
BlueJ Package
BlueJ Context File
BlueJ Template File

.defs - Linux Shadow Password Suite Configuration

The DEFS configuration files are related to Linux. The DEFS file is a Linux Shadow Password Suite Configuration. Linux is a family of open source Unix-like operating systems based on the Linux kernel.

Configuration files
- / -
Linux Shadow Password Suite Configuration related extensions:
TCP Wrapper Access List Data
Linux Filesystems Information Table
Linux Kernel Hardware Description
Linux netboot Script
Linux Configuration Options
Linux Socket File

Naturally, other applications may also use the .defs file extension. Even harmful programs can create .defs files. Be especially cautious with .defs files coming from an unknown source!

Can't open a .defs file?

When you double-click a file to open it, Windows examines the filename extension. If Windows recognizes the filename extension, it opens the file in the program that is associated with that filename extension. When Windows does not recognize a filename extension, you receive the following message:

Windows can't open this file:


To open this file, Windows needs to know what program you want to use to open it. Windows can go online to look it up automatically, or you can manually select one from a list of programs that are installed on your computer.

To avoid this error, you need to set the file association correctly.

The .defs file extension is often given incorrectly!

Based on searches conducted on our site in the past year, we have compiled a list of the most common misspellings. These frequent misspellings can cause confusion and hinder search accuracy. By providing this list, we aim to assist users in finding the correct information more easily and improving their overall search experience on our site.

These misspellings were the most common in the past year:

def, des, dfs, efs, refs

Is it possible that the filename extension is misspelled?

There is a possibility that the .defs filename extension is misspelled. To assist users in identifying potential errors, we provide a list of similar file extensions in our database.

Filename extensions similar to .defs:

Tribes 2 Game DES Data
Intuit QuickBooks Template
eSignal Formula Script
Doom 3 Map Definition Data
Area 51 Game DFS Data
GameGuard Plugin

Operating systems

At, we strive to provide a seamless user experience by ensuring compatibility with a wide range of operating systems. The following is a comprehensive list of the operating systems currently supported by

Windows XP/Vista, Windows 7/8/10, Windows 11, CentOS, Debian GNU/Linux, Ubuntu Linux, FreeBSD, macOS, Mac OS X, iOS, Android

If you find the information on this page useful, please feel free to link to this page.

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