Just been wrangling a large OBJ file, a sprawling industrial set/scene, that did not read its bundled ~30 KB MTL file. Yes, ~30 KB. Hand-loading those ~250 materials' calls to ~140 textures maps in Material room was totally impracticable, but I did first dozen from curiosity. Then thought to check the OBJ's MTL call. Opening ~32 MB OBJ file in Wordpad found path led deep, deep into a sub-folder on author's D: drive. Oops. Took longer to re-save than edit...

Question arises: If Poser can prompt to browse for a missing texture, albeit with legacy 'initial characters off field' bug, why is there no obvious way to browse for a strayed MTL ?? Or call an 'alternate' MTL ?? Could not find anything relevant in the 'manual'...