Yes, the project is in 24p and majority of the clips are in 24p NTSC 4:3. But this problematic clips are in 29.97 HD 16:9. I’ve tried changing the project settings back and forth when deleting the takes and re-syncing the clips with the different project settings. But it doesn’t seem to solve anything. The main problem is that I can delete the marks individually but can’t manually add new marks. Is there any thing else that I can try? Or basically ScriptSync wont work properly when mixing sample rates? Thanks for the response!