To enable Sync Lock for selected tracks, select the Toggle Sync Lock icon at the head of each video and audio track you want to lock.
Learn about how to use sync lock to prevent changes while working with clips in Adobe Premiere Pro.
Enabling Sync Lock on tracks allows you to determine which tracks are affected when you perform operations like insert, ripple delete, or ripple trim. If a clip is part of an operation, the track shifts regardless of its sync-lock state. The other tracks shift their clip content to the right only if their sync lock is enabled.
To enable sync lock for all tracks of a particular type (video or audio), Shift-click the Toggle Sync Lock icon at the head of any track of that type.
To disable Sync Lock on one or more tracks, select or Shift-click for all tracks of a type, the Toggle Sync Lock box again so that it contains no Sync Lock icon.