One of my colleagues recently changed his password. Since then, his domain account keeps locking out frequently even though he enters correct password. He asked me to investigate why does this happen? There are multiple reasons, why domain account locks out frequently. First of all, I suggest you to find out when user’s account got locked and on what Domain Controller (DC). If user logs on to more than 1 PC, it may be possible that one of the PC is still using expired password. You can use Lockout status tool offered by Microsoft. It’s free tool, CLICK HERE to download it. Using this tool, you can find out that account is locked on any particular DC. Once you’ve identified correct DC, check the event log of that DC to locate the PC name. If user doesn’t log on to any other PC, log in to his/her PC locally or remotely. Try to locate any services or schedule task running using user’s credential. You will have to restart services or schedule task using their current login detai...