DIAGNOSIS That's usually not the compressor itself, but vibration being transferred from the compressor into the cabinet and your floor. It's amplified if the unit isn't perfectly level or is touching something.
FIX Let's isolate it. 1) Unplug the unit. 2) Check the leveling. Use a small spirit level on top. Adjust the front feet by twisting them to get it perfectly level side-to-side and front-to-back. 3) Pull the cooler away from the wall and any furniture. Make sure nothing is touching it. 4) Place a thick, dense rubber mat (like a commercial kitchen mat) underneath it. This absorbs vibration. Plug it back in.
IF THAT DIDN'T WORK If the noise is more of a loud rattle or grinding, the internal fan blade might be hitting a wire or the condenser might be touching the cabinet. This would require carefully removing the rear panel to inspect and reposition—only if you're comfortable.
HEADS UP Some noise is normal, especially when the compressor first kicks on. It should settle into a steady, low hum. If the new noise is a loud clicking that happens repeatedly, unplug it and call for service—that's the compressor trying and failing to start.