You can lock Clips, Sequences, and Timeline Tracks.
Select the clip(s) and go to Clip menu | Lock or Unlock; or select the clip(s) and right-click on the selected clip(s), and select Lock or Unlock.
When a clip is locked, you can not easily delete the clip or the media files that it links to. Notice that I didn't say that it's impossible to delete the clip or the linked media files. First, it's obvious from the Unlock selection that clips and media can be unlocked from inside of Media Composer. But what's not obvious is that media files can be unlocked at the Operating System Level even when Media Composer isn't running.
You can determine which clips are locked by displaying the Lock column when the bin is in Text View. Details on displaying columns of data and creating Bin Views are in the Creating Bin views recipe in Chapter 2, Customizing Your Work Environment.
Select the Sequence(s) and go to Clip menu | Lock or Unlock; or select the Sequence(s) and right-click on the selected Sequence(s), and select Lock or Unlock.
When a Sequence is locked, it only locks it from being deleted.
When a Sequence is locked, it does not lock the media it refers to.
When a Sequence is locked, it can still be edited just as if it weren't locked.
You can determine which Sequences are locked by displaying the Lock column when the bin is in Text View. Details on displaying columns of data and creating Bin Views are in the Creating Bin views recipe in Chapter 2, Customizing Your Work Environment.
Enable the track(s) you want to lock and select Clip menu | Lock or Unlock; or lock/unlock tracks one at a time by right-clicking on a Track Selector | Lock or Unlock.
When a track is locked, you can not perform any editing functions on it. If you attempt to Spice, Overwrite, Lift, or Extract, you will be alerted that you Cannot edit a read-only track.
When a track is locked, a small lock symbol will appear in the Sync Locks column.