U2F is widely regarded as the best way to secure your important accounts since it relies on access to a physical key before the account will be unlocked. But what happens if you lose that key?
If you happen to lose your U2F key, the first (and really, only) thing you’ll need to do is remove that form of authentication from your accounts. You’ll need to jump onto a device that is already logged in to all of your accounts and remove that particular key as a form of authentication.
So, for example, if you need to remove a key from your Google account, head into My Account > Signing Into Google > 2 Step Verification. From there, click the little pencil icon next to the device name and remove it. Easy peasy.
Just do that for all the accounts where you’ve added your lost U2F key—make sure to do it before you need access to the account from a new device, lest you get locked out of that account.
That’s another reason it’s always good to have multiple forms of 2FA enabled on all accounts that support it, whether that be with backup codes or making sure all your account info is up to date.