Materials
6 checks, listed alphabetically.
Color Space Valid
Checks image textures used as normal, roughness, metallic, height, displacement, masks, or other non-color data and verifies that their image color space is set to non-color data. Also checks image textures used purely as color (Base Color, Emission Color, etc.) and verifies they are not set to Non-Color. Images used for both color and non-color purposes are skipped by default because one global image color-space setting cannot be correct for both uses. An image's Alpha output is ignored when it only drives Alpha / Opacity inputs, because color space does not affect alpha.
Material Assigned
Checks mesh objects for missing materials, empty material slots, and polygons assigned to invalid or empty material slots.
No Disconnected Shader Nodes
Checks materials for shader nodes that are not connected, directly or indirectly, to an active Material Output node.
No Orphan Materials
Checks for unused material datablocks, excluding protected, linked, asset, and Blender-managed materials.
No Unused Material Slots
Checks for unused material slots. Empty unused slots are reported and can be fixed automatically. Populated unused slots are ignored by default because they may be intentional, but can optionally be reported for manual review.
Texture Files Exist
Checks if Image textures reference external files that do not exist on disk. Objects using materials containing missing textures are reported so they can be selected directly in the scene.