When you try to log on to your computer, if you do not successfully log on after the first couple of attempts your account may unexpectedly be locked out.
For example, if your Account Lockout threshold has been set to five, you may be locked out after your third unsuccessful logon attempt.
This behavior may occur if the full name and the user name of the logon account are the same. When a logon attempt is not successful, Windows XP automatically retries the logon by using the logon account's full name. As a result, two logon attempts occur and are counted against your Account Lockout threshold.
For more information about the Account Lockout threshold, click Start and then click Help and Support. In the Search box, type account lockout, click Start searching, and then click Full-text Search Matches.
To work around this behavior, change the full name of the account so that it is different from the user name of the account. To do this, follow these steps:
Click Start, and then click Control Panel.
In Control Panel, click User Accounts.
Under pick a control panel icon, click User Accounts.
On the Users tab, click the user name that you want to change, and then click Properties.
On the General tab, change the full name so that it is different from the user name.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.