Comment thread and tracked changes limits

The total number of comment threads, both resolved and active, is limited to 500 threads per file. If you see that you have hit the limit on adding comments, you can delete some of the resolved threads to free up space.

You can view the list of resolved comments by clicking on the file tray icon in the top left of the 'review' pane (shown in this article: https://www.overleaf.com/learn/how-to/Track_Changes_in_Overleaf). From there you can delete resolved comments to free up space.

The total number of tracked changes is limited to 2000 tracked changes per file. If you see that you have hit the tracked changes limit, you can Accept or Reject some of the changes in order to free up space (please see: https://www.overleaf.com/learn/how-to/Track_Changes_in_Overleaf).

The track changes and comments limit is a per-file limit. Setting up your project to break long .tex files into multiple files may help. As moving text around with copy and paste can cause comments to become lost or detached, you should take care if you are reorganizing an existing project. Please see this article for suggestions on managing large projects: https://www.overleaf.com/learn/latex/Management_in_a_large_project