Since it didn't work in the original project I did on the prefab right click and selected Export Package.
Then in my new project after copying the prefab file only 7KB size: Screenshot of the prefab in the original project: Now I want to copy and use this prefab in other project/s too. In my original project after made changed to the GameObject in this case a door I dragged it to the Assets and a new prefab created. I will not see the prefab with all the materials textures. If I just copy the prefab file from folder to folder it won't work.
