Facebook messages are stored on the company’s servers for a period of three months. If you delete them, your account is locked and you can’t access it until Facebook decides whether to keep the messages or delete them.
To remove messages from both parties’ Messenger accounts, tap the message, then “More…”, choose “Remove”, and hit “Unsend.” The message will be erased from your side of the chat and the receiver’s side of the chat after you’ve tapped on “Unsend.” The term implies.
To permanently erase a message, go to Settings > Messages and select the ones you want to get rid of. Then, in the message options, choose to Remove for Everyone. The removed message will be replaced by an alert informing everyone in the chat that it has been erased. This also works in groups and one-on-one conversations.
No, you can’t see deleted communications or conversations. Deleting a message from your Chat list permanently removes it from your list. Keep in mind that removing a message or discussion from your Chat list does not remove it from the Chat lists of the people you spoke with.
Yes, you can delete a chat thread using Messenger. It is not possible to erase the conversation thread on either side. In other words, until you remove the chat thread yourself, you will be able to read old chats in Messenger.
Messages and conversations don’t actually vanish from the recipient’s account after you send them. If you remove a message or conversation on your end, it simply implies that it will be accessible on their account. You can, however, decide to delete a message after 10 minutes have elapsed since it was sent.
