Fig. 1. Edit warning on page tree
Fig. 2. Edit warning on page property form

TYPO3 does not lock a page in order to prevent two people from trying to edit it simultaneously. However, it does warn you that another user is trying to edit the same page as you. 

  • You should always look for the warning icon which appears in the page tree (Fig. 1).
  • You may also see a warning above the page properties form (Fig. 2).

In either case you should contact the other user before proceeding.