I’m new on the forum (not in ketchup used since version 8), currently version 19 pro on mac.
My problem is the following: in the textures window, some of them are double or even triple.
I tried to erase them one by one, to do it by re-registering my default template, nothing to do, the duplicates come back again and again in the previous order.
The doubled materials has been a problem on Mac for some users. It seems to be somehow related to one or more of the rendering extensions. there have been numerous threads on this in the past.
Materials that you have made in your own materials folder will come back if you delete them in a model and reopen the model. Check in this folder to see if that might be the case, and delete any that you don’t want in Finder: