Every five seconds, Citavi checks if changes have been made to an open project. Any changes will be saved automatically. You can continue working while Citavi saves.
Sometimes you may be working a bit longer in a field, such as an Abstract or Quotations field. If you see a Save button in the edit window you're working in, you can click it to be certain that changes are saved as you go.
When you close a project, Citavi checks one last time for changes and then saves them.
See also the Using Backups chapter.