What happened?
Before printing, if filament is already loaded on an MK4/S, MK3.9/S, or MK3.5/S equipped with the MMU3, the printer warns the user to confirm whether the loaded filament should be used for the print or if the current filament should be unloaded.
The displayed message is "Filament detected. Unload filament now? Select NO to start the print with the currently loaded filament".
Error name: Print preview MMU filament inserted
Error code: #26806 (MK4S) #13806 (MK4) #27806 (MK3.9S) #21806 (MK3.9) #28806 (MK3.5S) #23806 (MK3.5)
How to fix it?
Double-check the loaded filament, in particular if it matches the material that is set for the print. Select NO to not unload filament and start the print with the currently loaded filament. Otherwise, unload the filament.