I’m a retired U.S.real estate owner who used to install ceiling fans in my apartments(about 50).
I got good enough to install them blindfolded and never had this problem. I live in Asia now and didn’t want to screw up the installation(220-volt, different wires, etc.) so I had our condo(I own my apartment) maintenance guy do the installation. The fans here are either Chinese or American(Hampton Bay,etc.) After the installation, I clicked on all three speeds. The high speed blades produced a silent sound of air swishing, but the mid-speed and low-speed fans prodeuced a sound akin to rubbing. My first reaction was the blades must be unbalanced, but never having had this problem, is that the cause? Or should I check other sources?