OptiClean is a single build for Blender 4.2 LTS and newer, and works with both EEVEE and Cycles. It's pure Python with no external dependencies, so it runs on Windows, macOS, and Linux.

The most common cause is a pattern without a *. Patterns use * as a wildcard: *_BC matches a suffix, BC_* a prefix. A pattern with no * matches the file name exactly. Also check that the source folder is right and enable "Search subfolders" if your textures are nested.

OptiClean optimizes what it can measure: it reduces VRAM usage, file size, duplicate materials, and heavy data. Whether that speeds up a given render depends on your scene and hardware (for example, fitting textures into VRAM can let you render on the GPU). It does not promise a fixed speed-up, and the Render Data estimate is clearly labeled as an estimate, not a measurement.

Object-level actions (deleting meshes, merging slots, connecting texture nodes, re-pointing missing textures) are undoable with Ctrl+Z. Actions that remove file-level datablocks — orphan purge and material datablock merging — may not undo cleanly; OptiClean warns you before running those.