ERROR

Fluent closes unexpectedly (aborts) at random points during a session on Windows. The crash is intermittent and can go several sessions without happening.

After the graphics driver is changed to stop the crash, graphics windows (mesh, contours, plots) may open but stay solid gray with nothing drawn.

If the graphics driver variable is misspelled, the Fluent console shows the following at startup and falls back to DirectX 11:

Graphics driver currently in use: dx11
Warning:
Specified graphics driver "opengi2" is not available on the current runtime environment.
Selected dx11 instead, the most appropriate driver for it.

Software & Version

Fluent 2026 R1 on Windows 11. 

Description/Cause

Fluent supports several graphics drivers, and the best one depends on the machine's graphics hardware. On this system, the intermittent crash was tied to the DirectX 11 (dx11) driver. The HOOPS_PICTURE system environment variable sets which driver Fluent uses. Setting it to OpenGL2 stopped the crash but left the graphics window blank. A software-rendered driver brought the display back.

Solution

1. Close all Ansys applications.
2. Open the Windows Start menu, search for Edit the system environment variables, and open it. Administrator rights are required.
3. Click Environment Variables.
4. Under System variables, click New and create:

• Variable name: HOOPS_PICTURE
• Variable value: opengl2

Type the value in lowercase. The character after "openg" is a lowercase L, not a capital I.

1. Click OK to save, then restart the machine.
2. Launch Fluent and check the console. If it shows the "Specified graphics driver ... is not available" warning, the value is misspelled. Correct it and restart.
3. Load a case and display a mesh or contour. If the graphics window shows it, you do not need to change anything else.
4. If the graphics window stays solid gray, edit HOOPS_PICTURE, change the value to opengl2-mesa, restart the machine, and test again.
5. If the display is still blank, change the value to msw, restart the machine, and test again.
6. If none of these values restores the display, update the graphics card driver from the manufacturer's website. See ERROR - Cannot See Model in Graphics Area.

Note: opengl2-mesa and msw draw graphics in software, so the display can update more slowly on large models.