File sharing features prevent problems that can occur in a network environment where multiple users have access to the same file.
Open files are locked to prevent other users from making changes to the original while the file is being edited. When a user attempts to open a locked file, they receive a message warning that the file is being edited by another user. They are then given the option to open the file read-only. In this case they are not permitted to save to the locked file either until the original user relinquishes his lock by closing the file.