The symptom pattern

Mid-print, usually right as the AMS unloads or switches filament, the screen shows “the cutter is stuck.” It can happen once and never again, or it can come back every time the printer tries to cut filament.

What’s actually happening

The X1 Carbon’s AMS cuts filament with a spring-loaded lever in the toolhead: when the printer needs to cut, the tool head moves to the front, a top lever presses the cutter lever, the blade cuts the filament, and the lever is meant to spring straight back. A magnet in the lever and a Hall sensor in the extruder watch for that return. If the sensor doesn’t see the lever back in position within two minutes, the error fires — which means the message can mean either “the lever is genuinely stuck” or “the sensor didn’t see it return,” and those are different problems with different fixes.

Working through it

Open the toolhead and look at the lever directly. That one look tells you which branch you’re in.

Lever looks normal, not stuck. This is a detection problem, not a mechanical one, and every fix here is free. Start with Retry — on Support or Silk filament the lever can spring back a little late, and the error simply clears. If it keeps firing, clean the Hall sensor and its magnet of dust or filament debris and try again; a dirty sensor reports the same symptom as a genuinely stuck lever. Still no joy: the toolhead’s 10-pin connector can develop poor contact, and re-seating it — after clearing the silicone sealant off it with tweezers, which can take more than one attempt — resolves a surprising number of these. If none of that clears it and you have a spare extruder, swapping it in isolates whether the Hall sensor itself has failed.

Lever is actually stuck and won’t spring back. Check the hot end for a clog first. A clogged hot end raises the pressure on the filament between the extruder and the nozzle, and that extra pressure is what typically catches the blade and holds it down — clear the clog and the cutter usually frees itself. If the hot end is clean but the cutter keeps jamming anyway, unload the filament completely and press the lever by hand. If it still sticks with nothing in the extruder, the cause is friction between the cutter and the extruder’s inner wall, which Bambu attribute to manufacturing tolerance — their fix is removing the cutter and lightly dressing both sides of the blade before refitting it, not replacing the part. Last check: make sure the toolhead’s cooling-fan cable hasn’t drifted into the cutter lever’s path, since a trapped cable can physically block the return.

Verdict

Diagnose before assuming anything is broken — on this fault, “broken” is genuinely the least likely explanation. Most cases are the Hall sensor or a connector reporting something that didn’t actually happen, and every fix for that costs nothing. Even a real jam is usually a side effect of a clogged hot end rather than a failed part. The only outcome here that’s a hardware fault rather than a clean-and-retry job is a Hall sensor that keeps misreporting after everything above has been checked — and even then, it’s a support case because the fix is a spare part Bambu supply, not something to improvise.