All machines with the machine number 189442634 up to and including 190001700 are affected.
STIHL have identified that a limited number of TS410 and TS420 cut-off machines were assembled with the flywheel-to-crankshaft connection overtightened.
This could cause the flywheel to fail and break apart while the engine is running. A failure during the operation of the machine would pose a projectile hazard to the user or a bystander. A damaged flywheel is not apparent from a visual inspection.
You can find the machine number as per the image below.
If you have an affected product please take it to your local Stihl service centre, found on the link below, where it will be repaired free of charge by a Stihl qualified engineer.