Can you post a screenshot?
A solution is to delete all modifcations, save, restart the program and than remodify again. Pretty stupid since it took some time to modify.
You can delete this discussion
Thanks Simon, I'm glad you were able to solve your issue.
I wanted to see a screenshot because I don't believe Premiere Pro places watermarks on trial versions, it should behave exactly as the paid version.
I would guess that these watermarks are from trials of third party plug-ins. If you use native effects within Premiere Pro, you shouldn't see any watermarks.
Good luck on your project!
My guess would be that this is Premiere Elements, which DOES have a watermark applied, when used in the trial version. If this guess is correct, then this PrE FAQ Entry should be helpful: http://forums.adobe.com/thread/433730?tstart=30
As the OP has found, just adding the S/N, to convert from trial mode to full-paid mode, when one has an existing Project, done in the trial mode, will not remove the watermark from THAT Project - Removal of the Render Files is also required. Also, see Reply #8 for clarification from Adobe: http://forums.adobe.com/message/4797656#4797656
If the Timeline has been Exported (Shared, or Publish+Share in later versions of PrE), there is no way to remove the watermark from that output file. Also, one DOES need to Delete those Render Files, from the Project, to then output the Timeline without the watermark.
Hope that this helps, and you might want to Move this thread to the PrE Forum.