If you see "Not all lines are completed" in the progression panel in the right-hand part of the subtitle editor, as shown on the screenshot below:
it means that at least one subtitle lacks text or timing. Subtitles that have empty or untimed sells, cannot be marked as completed.
1. Check all the subtitles, either in the editor or in the subtitle view. Make sure you check the end of the subtitle set - typically (but not always) incomplete subtitles can be found there:
- In the editor
- In the subtitle view
2. If you find empty cells anywhere, fill them with text or delete them:
3. If you find subtitles that lack timing, sync or delete them:
4. When everything has been corrected, your progression panel will look as on the screenshot below:
Now you should be able to make a final review of your work (if necessary) and mark your subtitles as complete.