Mine started doing that as well. I cleaned it THOROUGHLY, checked for tiny slivers of thread and fuzz, etc, and it sewed fine for a while and then started showing the message again. I repeated the cleaning process again and evened oiled the hook. Sewed fine for a few days, then up pops the same error message. I thought the third time of cleaning would be the charm. Nope. Same message. Sooooo, the fourth time I got the error message to check the bobbin area, etc., I sat there looking at it for about thirty seconds wondering what would happen if I just keep sewing. It sewed perfectly without missing a beat. I now get the message once a month or so, but I just keep sewing and so far, so good.