Diagnosis
The debris shield rotates out of position. The shield is not correctly locked onto its mounting tabs on the gear case.
How to Fix It
Step 1: Rotate the shield to the desired position (typically with the opening facing away from the operator). Step 2: Locate the locking lever on the top of the shield, near the gear case. Step 3: Push this lever firmly downward until it clicks and engages. Visually confirm the lever is flush and the shield cannot be rotated by hand.
If That Didn't Work
The plastic tabs on the gear case or the shield itself may be broken or worn. Inspect for damage. A replacement debris shield (Milwaukee part number 42-69-2570) is required if the locking mechanism is broken.
Heads Up
Do not operate the trimmer without a properly secured debris shield. The shield protects the user from thrown debris and prevents line from tangling around the gear case.