<p><strong>Issue</strong></p>
<p>When reading email in your 3rd-party mail client (eg Outlook, Thunderbird, etc), you sporadically receive a pop-up stating:</p>
<p>"The UID of a message changed unexpectedly.  This typically indicates a server bug.  Your program may not function properly after this."</p>
<p>MsgSeqNum 000: Previous UID: 12345678, New UID: 12345789.<br />Protocol: IMAP<br />Server: imap.HyperOffice.com<br />Port: 143<br />Error Code: 0x800CCCDB</p>
<p><strong>Explanation</strong></p>
<p>This error occurs when you have both an IMAP connection open to a specific folder and also a WebMail session open looking at that same folder.  This is a known issue with the IMAP protocol.</p>
<p><strong>Workaround</strong></p>
<p>Navigate away from that folder in your browser or your 3rd-party mail client.  It is advised that you only access your mail through only one method at a time.</p>