Software & AppsOperating SystemLinux

How To Fix “Could not initialize GTK! Is DISPLAY env var/xhost set?” Error on WSL

Ubuntu 13

The Windows Subsystem for Linux (WSL) has made it possible to run Linux applications on a Windows machine seamlessly. However, running GUI applications like GTK can sometimes throw an error: “Could not initialize GTK! Is DISPLAY env var/xhost set?” In this article, we’ll walk you through the steps to fix this issue.

Quick Answer

To fix the "Could not initialize GTK! Is DISPLAY env var/xhost set?" error on WSL, you need to install an X server on your Windows machine, configure it correctly, and set the DISPLAY environment variable in your WSL terminal. This will allow GTK-based programs to run smoothly on WSL.

Understanding the Problem

Before we dive into the solution, it’s crucial to understand the problem. The error message suggests that GTK, a library used to create graphical user interfaces, could not be initialized. This is because it needs to communicate with an X server, which is not available by default on WSL. The X server is a program that manages the display and handles input devices for GUI applications.

Installing an X Server on Windows

The first step in resolving this issue is to install an X server on your Windows machine. There are several X servers available for Windows, such as Xming and MobaXTerm. Download and install one of these according to your preference.

Configuring the X Server

After installing the X server, you need to configure it. For Xming, you can use the -multiwindow option when launching it. This option allows each X application to run in its own window on the Windows desktop, instead of inside a virtual desktop.

For MobaXTerm, no additional configuration is required after installation. Just launch the program and it will start the X server automatically.

Setting the DISPLAY Environment Variable

Next, you need to set the DISPLAY environment variable in your WSL terminal. This variable tells GTK where to display the GUI. Use the following command:

export DISPLAY=:0

Here, :0 is the display number of the X server. If you’re running multiple X servers, you may need to adjust this number accordingly.

Testing the Setup

Now, you should be able to run GTK-based programs. Try running a GTK application to see if the error is resolved. If the application runs successfully, you have fixed the issue.

Troubleshooting

If you encounter the error “xhost: unable to open display “:0″” when running xhost +LOCAL:, it means that the X server is not running or not properly configured. Make sure you have launched the X server before running the xhost command.

Conclusion

Running GUI applications on WSL can be a bit tricky due to the lack of a built-in X server. However, by installing an X server on Windows and configuring it correctly, you can run GTK and other GUI applications smoothly. Remember to set the DISPLAY environment variable correctly in your WSL terminal. With these steps, you should be able to resolve the “Could not initialize GTK! Is DISPLAY env var/xhost set?” error.

What is an X server?

An X server is a program that manages the display and handles input devices for GUI applications. It is necessary for running GUI applications like GTK on WSL.

Which X server should I install on Windows?

There are several X servers available for Windows, such as Xming and MobaXTerm. You can choose one based on your preference. Both Xming and MobaXTerm are commonly used and work well with WSL.

How do I configure Xming?

To configure Xming, you can use the -multiwindow option when launching it. This option allows each X application to run in its own window on the Windows desktop, instead of inside a virtual desktop.

Do I need to configure MobaXTerm after installation?

No, you don’t need to configure MobaXTerm after installation. Just launch the program and it will start the X server automatically.

How do I set the DISPLAY environment variable in WSL?

To set the DISPLAY environment variable in your WSL terminal, use the command export DISPLAY=:0. Here, :0 is the display number of the X server. Adjust this number if you’re running multiple X servers.

What should I do if I encounter the error “xhost: unable to open display “:0″”?

If you encounter this error when running xhost +LOCAL:, it means that the X server is not running or not properly configured. Make sure you have launched the X server before running the xhost command.

How can I test if the setup is working correctly?

You can test the setup by running a GTK-based application. If the application runs successfully without the "Could not initialize GTK! Is DISPLAY env var/xhost set?" error, then the setup is working correctly.

Are there any alternative solutions to running GUI applications on WSL?

Yes, another alternative is to use a remote desktop solution to connect to a Linux desktop environment running on a virtual machine or a remote server. This allows you to run GUI applications without the need for an X server on Windows. However, it requires more setup and resources compared to using an X server on WSL.

Leave a Comment

Your email address will not be published. Required fields are marked *