I run Instant Messaging (IM) on my Microsoft Exchange 2000 Server system. Every so often, IM logs me off for no apparent reason. When I try to log back on, I experience an authentication failure. After I wait a little while, I can log back on. Do you know what's going on?

Microsoft has identified this situation as a problem that can occur when you run Exchange 2000 and the IM service on the same computer. Exchange 2000 Service Pack 2 (SP2) contains a fix. For more information about the problem and about obtaining SP2, see the Microsoft article "XCCC: Instant Messaging Clients Are Suddenly Logged Off and Cannot Immediately Reconnect" (http://support.microsoft.com/default.aspx?scid=kb;en-us;q303991).

If you don't want to install SP2, you need to contact Microsoft Product Support Services (PSS) for a separate patch (i.e., dsaccess.dll 6.0.4720.24—English version). Microsoft typically doesn't charge for calling to obtain patches of this nature. Be aware, however, that you must run Exchange 2000 SP1 or later for the patch to be effective.