My YubiKeys Suddenly Started Saying This Key Doesn't Look Familiar

Question

When I tried to sign into windows using either of my 2 YubiKeys windows displayed a message box with "This key doesn't look familiar". I was able to login with the authenticator app and deleting and recreating the passkeys allows me to login with my YubiKeys again but I am worried about why this happened.

Answer 1

Hello,

Thank you for posting question on Microsoft Windows forum!

Based on the error message This key doesn't look familiar when using either of my 2 YubiKeys. This error message typically indicates that the passkey stored on your YubiKey is not recognized by your Windows account. The followings are the potential reasons for triggering that error.

1.Passkey Desynchronization or Corruption:

• Windows Identity: Your Windows login, especially if linked to a Microsoft account, relies on a synchronized record of your registered passkeys. If this record becomes corrupted or desynchronized between your local Windows installation and Microsoft's cloud (or your local system's credential manager), the YubiKey's passkey might not match what Windows expects.
• YubiKey Data Glitch: While YubiKeys are designed for high reliability, it's theoretically possible for a minor data glitch on the key itself or during a previous registration process to cause an issue. Re-creating the passkey effectively wipes the old (problematic) entry and creates a fresh, correctly recognized one.
• Windows Hello for Business (WHfB) Issues: If your device is managed by an organization and uses WHfB, more complex issues like certificate expiration, policy changes, or domain-level synchronization problems could cause this.

2.Windows Update Interference:

• Sometimes, major Windows updates can subtly alter how credential providers or FIDO2/passkey mechanisms function. While rare, an update might inadvertently break the link between your existing YubiKey passkeys and your Windows profile.

3.Temporary System Glitches:

• A one-off software glitch in Windows or a conflict with other installed software could temporarily prevent the proper recognition of the YubiKey. Your workaround of deleting and re-creating the passkeys would reset this.

4.The Plausible explanation of when deleting and re-creating the passkeys fixing the issue are:

• Removed the old, unrecognized credential from your Windows user profile and your YubiKey's internal storage (for that specific passkey).
• Established a brand new, clean registration, allowing Windows to correctly associate the new passkey on your YubiKey with your account.

The following suggested steps might probably help prevent the issue occurring again:

1.Keep Windows Updated:

• Ensure your Windows operating system is always up to date. Microsoft regularly releases patches and improvements, which can address underlying issues with security features like passkeys.

2.YubiKey Firmware and Software:

• YubiKey Manager: Periodically check for firmware updates for your YubiKey using the YubiKey Manager application. While less common for this specific error, keeping your YubiKey's firmware current is good security practice.
• Ensure any YubiKey-related software (like YubiKey Manager if you use it for other functions) is also up to date.

3.Have a Backup Login Method:

• This is crucial. Your ability to log in with the authenticator app saved you. Always have at least one reliable backup method for your Windows login, whether it's a strong password, a PIN (separate from any YubiKey PINs), or another security key.

4.Monitor Windows Event Logs:

• If this happens again, checking the Windows Event Viewer (specifically under "Security" or "System" logs) around the time of the failed login attempt might provide more technical details about why the key wasn't recognized. Look for errors related to FIDO, WebAuthn, or credential providers.

The below article is for your further reference regarding the error message.

• https://support.secureauth.com/hc/en-us/articles/12609310533652--This-security-key-doesn-t-look-familiar-error-is-thrown-when-using-a-Yubikey-for-MFA

Hope the above information is helpful!

Answer 2

Not Fixed

Previously I thought I had fixed it with the steps below, but it turns out if I login with my authenticator app then reboot, the YubiKeys start to work without touching the authenticator app. I'll leave the original text here below.

(Not Correct) Fix

It happened again. I was able to resolve the issue (hopefully for good) by doing this:

Clear the Ngc Folder (Resets PIN/Security Key Data)

Open File Explorer and enable "Hidden Items" in the View tab.

Navigate to:

C:\Windows\ServiceProfiles\LocalService\AppData\Local\Microsoft

Right-click the Ngc folder → Properties → Security → Advanced.

Change ownership to your user account, check "Replace owner on subcontainers and objects," apply changes.

Open the Ngc folder and delete all its contents.

Restart the PC

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I did this and my YubiKey started to work again without re-registering it.