I'm experienceing the same thing here, mac os 15.3.1, photoshop 26.3, but it has only started in the last couple of days, so presumably it popped up with the recent photoshop update to 26.3 on my machine. Sure is frustrating though! ... View more

If you open the mtl file with notpad, you should get a list of all material maps that are associated with the obj file. If there are none listed. you need to step back into Photoshop and look at how the texture files are set up for your object (in materials properties)   Dave ... View more