0xC0000234: Event ID 4625 account locked out
Likely causes
- Too many wrong passwords hit the domain's account lockout threshold.
- A device or service keeps using an old password and locks the account again.
- A password guessing attack.
How to fix it
- On a domain controller, find Event ID 4740 in the Security log. Its Caller Computer Name shows which machine caused the lockout.
- On that machine, find what uses the old password: services, scheduled tasks, mapped drives, saved credentials, or a phone.
- Unlock the account (in Active Directory Users and Computers, or
Unlock-ADAccount -Identity <username>). This needs account admin rights. - Reset the password if the user doesn’t know it, and update it on every device.
- If the source is unknown, don’t just keep unlocking. Escalate as a possible attack.
Checked against: learn.microsoft.com, learn.microsoft.com, learn.microsoft.com