OMG. I am SO glad that I am not the only one to do this. I COULD NOT figure out what was up with my rotary cutter when this happened. I'd just changed the blades, but the thought that I had two blades in NEVER crossed my mind. I actually took my cutter to a friend, and we fretted about it for close to 20 minutes before we (truthfully SHE) figured out that I had two blades in. The good thing is that it will never happen again.