Anycubic Filament Runout Detected — Reload Guide

What Does This Error Mean?

Filament runout on Anycubic FDM printers means the runout sensor (a small lever switch the filament passes through) sees no filament feeding.
Either the spool is empty, the filament has snapped before the sensor, or the sensor is stuck.
Pause is automatic.
Load a new spool, push fresh filament through the sensor and into the extruder, then press Resume on the touchscreen.

Affected Models

Anycubic Vyper
Anycubic Kobra
Anycubic Kobra 2
Anycubic Kobra Plus

Common Causes

Spool actually empty
Filament snapped before reaching the sensor
Sensor lever stuck (worn switch or filament debris)
Filament tangled on the spool
Extruder grinding caused filament to break before the sensor

How to Fix It

Confirm the spool status.

Look at the spool on the holder.
Is it empty, or is filament still wrapped around it?
If still on the spool, follow the filament back from the printer — there's a break somewhere between the spool and the sensor.
Snip cleanly and rejoin.
Cut a clean tip on fresh filament.

If you're loading a new spool, cut the leading edge at a 45-degree angle with side cutters.
A clean angled tip slides through the sensor and PTFE smoothly.
A blunt tip catches and won't load.
Feed filament through the sensor.

Slide the new filament through the runout sensor (the small box just before the extruder).
You should feel the lever inside click as the filament passes.
That click confirms the sensor is reading.
Continue feeding until you reach the extruder gear.
Use the touchscreen to load.

From the LCD: Filament → Load.
The hotend heats up and the extruder pulls filament through automatically.
Stand by — when fresh filament extrudes from the nozzle, you've successfully loaded.
Wipe the nozzle clean.
Resume the paused print.

Press Resume on the touchscreen.
The print continues from where it paused.
Watch the first layer after resume — sometimes the layer change is visible.
If quality degrades after resume, that's normal and not a printer fault.

Frequently Asked Questions

Why does my filament keep snapping?

Filament that's been sitting open for months absorbs moisture and becomes brittle.
Brittle filament snaps as it bends through the Bowden tube or extruder gear.
Dry filament before printing — a food dehydrator at 50°C for 4 hours works for PLA.
Store opened spools in airtight bins with desiccant.

Can I disable the runout sensor?

Yes, in the LCD settings.
But you shouldn't.
If filament runs out mid-print without pausing, the print continues uselessly with the extruder grinding empty.
Worse, the part-cooling fan keeps blowing on the now-cold hotend and you may not notice until much later.
Leave the sensor on.