Facebook – “Unrecognized browser or device” email received from Facebook

You got this email that means you have set Get alerts about unrecognized logins in Security and Login Settings section and have chosen to receive your alerts with your email account.

So when you or someone else login your account in a new browser (where you have never logged-in before or you have just cleared browsing history of known browser), Facebook sent an alert (through email or Facebook notification or both, depends on settings) to you to recognize the device.

This is a legitimate email from Facebook.

Here what you should do:

• When you receive a login alert, you can tell us if you recognize the login activity by clicking or tapping This was me.
• If you don't recognize the login activity, click or tap This wasn't me and we'll help you reset your password and secure your account.
• You can save a device or browser to your list of trusted browsers or recognized devices. This way, you won't get alerts about the computer or mobile device you usually use to log into Facebook. Don't choose this option if you're using a public computer (such as one in a library or cafe).

Learn more about account security:
How to get alerts about unrecognized logins
If you don’t recognize a location in the Where You're Logged In section of my Facebook account
How to log out of Facebook on another computer, phone or tablet