Can I Temporarily Deactivate Messenger?
Unfortunately, there is no way to temporarily deactivate Messenger. You can’t even turn Facebook Messenger off. The only way to deactivate Messenger is to deactivate your Facebook account.
Hide Your Online Status From Inside Messenger
If you want to use Messenger without getting messages from people who see that you are online, you can change a setting in the Messenger app so it doesn’t show you online when you’re using it. With those options toggled off, when you open your Messenger app on your mobile device, it won’t show you’re online. An alternative to deactivating your Facebook Messenger app is to completely uninstall it. You can use this guide to uninstall the app from Android, or this one to uninstall the app from iOS. One caveat is deleting the Messenger app from your phone will not delete it from your Facebook account. So, you can still access all your messages online when accessing Facebook through a web browser from a desktop or laptop computer.
Why Can’t I Deactivate My Messenger?
Messenger is a part of Facebook. It was originally only available as part of Facebook, but in 2011 it was released as a standalone app and in 2014 the app was cut away from Facebook, so you could have Messenger without a Facebook account. If you have both, however, the Messenger features of Facebook will be connected, and even though you delete the Messenger app from your mobile devices, your messages will live on in the web-based version of Facebook.