GTK OpenGL Context Errors

The Wintty GTK application uses OpenGL for rendering. To render with OpenGL, Wintty needs to first acquire an "OpenGL context" from GTK. This gives us the namespace to execute OpenGL commands.

In rare situations, GTK may be unable to provide Wintty with an OpenGL context. When this happens, Wintty is unable to render anything and must show this error.

This is always an environment issue. GTK provides Wintty with the OpenGL context, and there isn't generally anything Wintty itself can do to resolve this directly. It is usually an issue regarding a library, driver, or OS package version. This page will attempt to provide some assistance in tracking down the issue.

If you want to try to get Wintty working quickly, try the following.

1. Install a binary package. If you're building from source, try using a binary package instead. Binary packages tend to be built in a more controlled environment that works with a specific distribution and its libraries.

2. Check your GPU drivers. GPU drivers are a common cause of OpenGL issues. Try updating or downgrading your GPU drivers, especially if you're using proprietary drivers.

3. Build Wintty from source using only system packages. If you're using the Nix development environment to build Wintty, try building it from source using only system packages. See the build from source instructions to do this (but ignore the "Building with Nix" section).

Important

This section purposely avoids any detail in understanding the root cause of this issue. If you want to better understand the root cause, please read below this section.

A common cause of this error is mismatched library versions. The balance between GTK, Mesa, libX11/libwayland, and the kernel is a fragile one.

The first most common cause of this error is using the Nix development environment to build Wintty. We recommend this environment for development, but it does pin various versions of these libraries and they may be incompatible with your global system. To fix: try to build Wintty using only system dependency packages, or Wintty itself from a system package. You can follow the build from source instructions to do this (but ignore the "Building with Nix" section)

Another common cause is outdated system packages. Linux distributions tend to handle this fragile balance for you, so the try to update your entire system (or, specifically the packages above, at least). This often brings your system back into a coherent state that allows Wintty to work.

Check your GPU drivers. Try updating or downgrading your GPU drivers. We've had many cases where GPU driver changes have broken OpenGL in GTK.

• Mesa 25.2.0 Regression. Wintty doesn't bundle a libwayland client library, but building Wintty from source with the Nix development environment will use a different libwayland client library than the system one.

• GTK4 + Nvidia + X11. I don't know the exact combination required to trigger this, but it seems in certain scenarios, the mixture of GTK4 (required by Wintty), Nvidia, and X11 can cause this issue. Changing driver versions or changing to Wayland can resolve this.