We have a number of clients using Outlook 2007 with IMAP mailboxes. Recently our ISP made some changes to their mail servers, since when we are seeing the following problems:
Some (but not all) users do not have their mailboxes updated. Renaming the .PST file or creating a new Outlook profile fixes the problem, but only temporarily; within a day the problem is back. Thunderbird and BlackBerry clients are not affected and always work fine.
The ISP assures us that their servers conform to IMAP specifications and are working correctly. Outlook 2007 is patched to SP2 and all later updates through MS Update. POP3 accounts work correctly in Outlook.
Any ideas appreciated!