Buzzzzzzing!

[mmukav]

I have a buzz. Seems to be coming from the tailpiece cover. (although after I humidified the mando the buzz went away--for awhile). If the tailpiece cover is rattling, what do I do? It seems to fit pretty tight now.

[Brian Aldridge]

set a piece of felt, leather or other padding between the cover and the strings

[Rroyd]

Remove the cover and see if that eliminates the buzz. If so, you could try curing it by putting a thin piece of leather or felt on the inside of the front edge of the tailpiece cover. If that works, you could use double-sided tape or glue to hopefully make a permanent cure. If the buzz is still there with the cover removed, check to see
if it coming from a vibration between a string and the tailpiece itself. The cure is the same, except
you place the material between the tailpiece and strings. If that isn't the problem, start looking for
something loose that reacts to certain vibrations. Is your endpin secured with a screw, or is the tailpiece fastened on with several screws? The former is sometimes the culprit on buzzing guitars.
Washers are a regular culprit as well, and I've seen several with loose pickguard hardware that would buzz. Good luck in your search.