NC Litho · Docs

If Litho flashes a spinner and closes, update to the latest release. If it still closes, set the environment variable WGPU_BACKEND to dx12 and start it again.

Symptoms

Fix

  1. Install the latest release. Litho remembers a start that never showed a window and tries the next graphics backend on the following start. On Windows the order is DirectX 12, Vulkan, then OpenGL, and the status bar says when it switches. A reporter who could not start 0.5.0 on Windows 11 Enterprise wrote that 0.6.0 launched without trouble (issue #273).
  2. If it still closes, set an environment variable named WGPU_BACKEND with the value dx12. Start Litho from a shell where it is set, or add it in Windows settings for your account. People who hit this crash with an AMD graphics driver reported that Litho starts with WGPU_BACKEND=dx12. dx12 also avoids Intel's Vulkan driver (igvk64.dll), which crashed in issue #192.
  3. Start Litho again.

Setting WGPU_BACKEND also turns off the automatic fallback. Other accepted values are vulkan and gl, and a comma-separated list lets the graphics library choose among them. Do not pick vulkan on Intel graphics or gl on AMD graphics: those are the drivers in the crash reports.

Why this happens

Litho draws the canvas on the CPU and uses the graphics card only to show the interface. Some graphics drivers crash while the window is being set up, and a crash in a driver ends the program before Litho can react. One AMD laptop's Vulkan driver crashed on the first frame, which is why DirectX 12 is the default on Windows.

Start the backend search over

Litho keeps its record of failed backends in a file called gpu.json in its settings folder, the one that holds ui.json, prefs.json and the logs folder (%APPDATA%\Litho\logs\ is the log folder on Windows). Delete the file to start the search again. The list also starts over after every backend has failed, and with a new Litho version.

Still stuck?