The modern messenger app does not really deactivate after you have deactivated your facebook account.You have to do it manually.Or you can do it at the time they ask also to deactivate messenger,when you are deactivating facebook account.
If you are speaking about only deleting the Facebook messenger app you can force stop it, clear content, clear its cache and uninstall. Should you decide to reinstall it again you will have to sign in the app again.
If you are talking about deleting both Facebook and facebook messenger you just simply forcestop, delete content, clear cache on the facebook messenger app then uninstall it. Then go to facebook and delete the account.
Understand that if you keep your facebook account the website versions always has the facebook messenger included and you cannot sign out of one or delete one completely without doing so to the other in the browser version.
To deactivate Messenger after you’ve deactivated your Facebook account:
- Open Messenger.
- Tap your profile picture in the top left corner > Privacy & Terms > Deactivate Messenger.
- Enter your password and tap Continue.
- Tap Deactivate.
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