◾Chain brake is engaged.
◾◾Pull the chain kickback brake handle backward toward the front handle.
◾Debris in bar groove.
◾◾Press the saw chain against the wood, move the chain saw back and forth to discharge the debris.
◾◾Remove battery pack, then remove side cover, and remove the chain and manually clean the bar groove.
◾Debris in side cover.◾◾Remove battery pack, then remove side cover and clean out debris.