Hello guys. So recently I started to have a problem with material thumbnails which are showing black icons in the material library. The materials work on objects and render just fine. It happened when I cleaned my cache and duplicit files because I needed to free up some space on my /C drive. I tried multiple commands mentioned in other posts, such as TestRestoreLibraryFileAssociations and TestClearRDKCaches and DownloadLibraryTextures (even though in Rhino default material library I can see thumbnails just fine. I even tried to repair rhino and nothing seems to work. Thank you for any suggestions. 
System info:
Windows 11 (10.0.26200 SR0.0) or greater (Physical RAM: 15GB)
.NET 8.0.22
Computer platform: LAPTOP - Plugged in [60% battery remaining]
Hybrid graphics configuration.
Primary display: AMD Radeon™ Graphics (AMD) Memory: 1GB, Driver date: 10-29-2020 (M-D-Y).
Integrated accelerated graphics device with 4 adapter port(s)
- Windows Main Display is laptop’s integrated screen or built-in port
Primary OpenGL: NVIDIA GeForce RTX 2060 with Max-Q Design (NVidia) Memory: 6GB, Driver date: 10-29-2025 (M-D-Y). OpenGL Ver: 4.6.0 NVIDIA 581.80
Integrated accelerated graphics device with 4 adapter port(s)
- Video pass-through to primary display device
OpenGL Settings
Safe mode: Off
Use accelerated hardware modes: On
GPU Tessellation is: On
Redraw scene when viewports are exposed: On
Graphics level being used: OpenGL 4.6 (primary GPU’s maximum)
Anti-alias mode: 4x
Mip Map Filtering: Linear
Anisotropic Filtering Mode: High
Vendor Name: NVIDIA Corporation
Render version: 4.6
Shading Language: 4.60 NVIDIA
Driver Date: 10-29-2025
Driver Version: 32.0.15.8180
Maximum Texture size: 32768 x 32768
Z-Buffer depth: 24 bits
Maximum Viewport size: 32768 x 32768
Total Video Memory: 6 GB
Rhino plugins that do not ship with Rhino
Rhino plugins that ship with Rhino
C:\Program Files\Rhino 8\Plug-ins\Commands.rhp “Commands” 8.25.25314.11001
C:\Program Files\Rhino 8\Plug-ins\WebBrowser.rhp “WebBrowser”
C:\Program Files\Rhino 8\Plug-ins\rdk.rhp “Renderer Development Kit”
C:\Program Files\Rhino 8\Plug-ins\RhinoScript.rhp “RhinoScript”
C:\Program Files\Rhino 8\Plug-ins\IdleProcessor.rhp “IdleProcessor”
C:\Program Files\Rhino 8\Plug-ins\RhinoRenderCycles.rhp “Rhino Render” 8.25.25314.11001
C:\Program Files\Rhino 8\Plug-ins\rdk_etoui.rhp “RDK_EtoUI” 8.25.25314.11001
C:\Users\Ivka\AppData\Roaming\McNeel\Rhinoceros\packages\8.0\PanelingTools\2024.8.20.677\PanelingTools.rhp “PanelingTools”
C:\Program Files\Rhino 8\Plug-ins\NamedSnapshots.rhp “Snapshots”
C:\Program Files\Rhino 8\Plug-ins\MeshCommands.rhp “MeshCommands” 8.25.25314.11001
C:\Program Files\Rhino 8\Plug-ins\RhinoCycles.rhp “RhinoCycles” 8.25.25314.11001
C:\Program Files\Rhino 8\Plug-ins\Toolbars\Toolbars.rhp “Toolbars” 8.25.25314.11001
C:\Program Files\Rhino 8\Plug-ins\3dxrhino.rhp “3Dconnexion 3D Mouse”
C:\Program Files\Rhino 8\Plug-ins\Displacement.rhp “Displacement”
C:\Program Files\Rhino 8\Plug-ins\SectionTools.rhp “SectionTools”
