Greetings! I have a problematic Vista Ultimate wireless laptop on a domain that exhibits strange behavior when taken off-site. I'd sure appreciate some thoughts on what the problem might be. When the laptop is used in-house, it works normally, and is used by two people. Person "A" is the primary user, Person "B" is a secondary user who logs on infrequently. Domain authentication works normally and happily. At times, however, when the laptop is taken off-site and introduced into a different wireless network with no access to the domain, strange and inconsistent logon behavior ensues. When Person "A" attempts to log on, they receive two messages: "The System Event Notification Service failed the logon" "The trust relationship between this computer and the primary domain has failed." Yet, moments later, when Person "B" logs on to the same laptop at the same venue, the logon succeeds and the laptop operates normally. Presumably, both logons would be accomplished via cached credentials, so there's no reason at all to conceive that either account should be handled differently. However, that is precisely the situation I see. Something is apparently causing Person "A"'s logon effort to be handled in an unusual way I cannot explain nor stop. When this laptop is returned to its primary location, normal operation resumes, all users can perform normal domain-based logons, and no errors are experienced. If it were merely a problem of not being on the same wireless network, and away from the domain, I would expect to see something along the lines of a "Domain controller could not be contacted..." message, but such never appears; and, presumably it would be experienced by all users, not just one. It almost acts as though the cached credentials for Person "A" are corrupt or non-existent, neither of which makes sense. Other laptops used by multiple individuals (using varying combinations of XP, Vista, and Windows 7) and taken off-site have *never* experienced this behavior. They've operated with cached credentials just as you would expect. I suppose a complete rebuild might solve the problem, but I'd rather not go nuclear on this particular box if it isn't necessary. Surely there is an explainable, if oddball, mechanism at work here causing this problem. Many thanks in advance for the help. -David