In Final Cut Pro, go to Preferences>General and click the Audio Units: “Validate on Next Launch” button. Then restart Final Cut Pro and your plugins will be functional again. To prevent this issue in the future, try using fewer instances of a CrumplePop audio plugins on your timeline. You can use a compound clip to place many clip segments into one clip, then only use CrumplePop audio plugins on that compound clip to make processing more smooth.