Adding a YubiKey to my account double-escapes my display name's apostrophe as "'" in ykman

It's the display name on my account, not my password.

Hello I can't think of a display name,

Welcome to the Microsoft Q&A and thank you for posting your questions here.

I understand that you are encountering an issue where your password is being altered (double-escaped) during YubiKey (FIDO2 security key) registration in Microsoft Entra ID.

This issue is not caused by YubiKey, Entra ID policy, or configuration errors. It is a string encoding problem triggered by special characters in the password. The only reliable and permanent fix is: Update the password to remove escape-sensitive characters and retry registration. - https://github.com/Azure/azure-sdk-for-net/issues/39434

You can do the followings to resolve it:

• Update the account password to remove escape-sensitive characters such as \, ", and '
• Use only supported and stable characters (letters, numbers, and standard symbols)
• Re-attempt YubiKey registration through the Microsoft Security Info portal after the password change

After replacing the password to avoid encoding conflicts, the YubiKey registration process completes successfully without further authentication errors.

Use the below resource links for guidance on secure registration and supported authentication methods:

• https://support.microsoft.com/account-billing/set-up-a-security-key-as-your-verification-method-2911cacd-efa5-4593-ae22-e09ae14c6698
• https://learn.microsoft.com/entra/identity/authentication/howto-authentication-passwordless-troubleshoot
• https://learn.goodhearttech.org/microsoft/microsoft-365-user-guides/setting-up-a-yubikey-hardware-mfa-token-with-microsoft-365

I hope this is helpful! Do not hesitate to let me know if you have any other questions, steps or clarifications.

Please don't forget to close up the thread here by upvoting and accept it as an answer if it is helpful.