Why can't I edit a document that has been checked out?
You cannot edit the document because it has been checked out by another user who has not yet checked the document back in. This is to prevent the creation of several different copies in M-Files. With system administrator permissions, the document can be forced to be checked in, but the changes made to the document during the checkout will then be lost.
Sending a check-in request
If you need to edit a document that is currently checked out to some other user, you can send the user a check-in request by right-clicking the document and selecting Send Check-in Request from the context menu. The user then receives an e-mail message informing them that you are requesting the document to be checked in. The message also contains a link to the document in question. The check-in request is sent to the e-mail address associated with the user's login account.