University of Leeds


Upgrade to Microsoft Exchange 2007 - Completed

IMAP Access to Exchange Mailboxes

View pages in this section

ISS has tested access to your mailboxes from several email clients which use IMAP to access the Exchange servers.  Tested end clients include Entourage, Thunderbird, Pine, Alpine and Apple Mail.  The testing completed does not constitute support for any of the stated clients but has been completed to help identify general issues with IMAP access to the service. 

The following table lists any known issues, current status of the issues and possible resolutions.

Known IMAP Issues
Client Affected Issue Description Current Status / Resolution 
All IMAP clients E-mails flagged as "important" do not carry the "X-Priority" or "Priority" headers when received by IMAP clients Microsoft have confirmed a fix will be available in the next released maintenance pack.
All IMAP clients Users of Outlook Web Access who do not use Internet Explorer can only use the Outlook Web Access Light interface. This interface does not allow users to create email filtering rules  or access to public folders.

The recommended options for access to these facilities is to use the remote and mobile access service (RMAS) from From here access to either the full Outlook client or Internet Explorer and can provide the necessary features.

All IMAP clients A blank email message is seen which appears to originate from EV and has a text attachment.  This message vanishes automatically after a short period of time.  It continues to occur on a twice daily basis.

This behaviour has been confirmed with the providers of our email archiving solution as a bug in the Microsoft Exchange IMAP service.  The issue has been raised with Microsoft and is currently under investigation. 

The message can be deleted / removed with no impact. 

All IMAP clients The 'Reply To' and 'Read' status information for an email managed using Outlook or OWA is not displayed when viewing the same email through an IMAP client.  Equally any email with 'Reply To' or 'Read' status informataion added by an IMAP client will not be shown in Outlook or OWA.

Avoid moving between applications to maintain a consistent view of email status information.

Pine and Alpine

Exchange reports the RFC822.SIZE property of messages incorrectly. As a result when copying a message; 
- Pine generates an error stating the message has shrunk and the copy action fails.
- Alpine generates an error message.  Users may elect to continue (or abort) the copy action.  

There is a resolution to this issue which ISS may apply to your mailbox.


Pine and Alpine

When opening multi-part messages the client unexpectedley crashes.  An example is when opening emails containing attached emails.

This is an incomptability between the Exchange IMAP Service and Pine/Alpine as a result of  Exchange not following standards for encoding multi-part messages. 

A call has been raised with Microsoft and we are awaiting a response. 

Pine and Alpine

When opening digitally signed messages, some of the content is not readable.

Save the message to a local Pine Mailbox and read it from there.

Pine and Alpine Blank truncated messages may appear occasionally in the users Inbox.  This happens very infrequently.

The reason for this behaviour is unknown - and there has been no identified impact of this. 

The meesage can be deleted.

Pine and Alpine

A warning 'Unknown message data' is shown in response to an invalid Exchange Server response.

The warning can be ignored.
Pine and Alpine Unexpected disconnections may occur from the IMAP server with the following message.
'Server Unavailable, 15'   


We are investigating the cause. Possible workarounds include.

  • Reduce the number of messages in your Inbox.
  • Avoid using multiple IMAP clients connecting to the server at the same time. 
  • Disable any client-side filters.
Pine, Alpine, and all IMAP clients which perform an online IMAP search. Searching a mailbox for an email address will not return any results.  

Microsoft are aware of this issue but do not intend to provide a fix within the current version of Exchange. 

Pine, Alpine and Thunderbird with client side message rules applied  The IMAP Inbox disconnects unexpectedley. This problem occurs when the client side rules perform a server side search against 4 or more email addresses.

This issue has been reported to Microsoft and is pending a response.  Workarounds include; 

1) Create Exchange server side rules to replace your client side rules using the Outlook client available from any platform at

2) Split your client side message rules so that fewer email addresses are searched by each rule.  


Contact us

Telephone: + 44 (0) 113 343 3333

Send your feedback or find key contact details.