I see an Unread Mail count on the logon screen of WIndows XP. This would be handy if it would indeed display the correct amount of unread items.
Is there a way I can correct this count or can I simply disable it otherwise?
The Unread Mail count on the logon screen of Windows XP is the combined number of unread items for all accounts or mail applications that expose their unread count. Aside from Outlook, this can also be for instance Outlook Express or Windows Live Messenger.
If you want to fix the unread item count, then you can do so by removing the accounts you no longer use from the registry. A guide on how to do that can be found here.
If you want to disable the feature altogether, then you can do that via the registry;
Key (current user only): HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\UnreadMail
Key (all users): HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\UnreadMail
Value name: MessageExpiryDays
If this value name is missing, the default is assumed which is 3 (days).