The following are known issues associated with the transition of messages from ACS to Exchange.

All mail clients:

  1. There is a window of less than five minutes (at the beginning of the migration process) during which mail sent from within Exchange to the newly-created Exchange account will bounce.
  2. Mail forwarding settings, mail filters, and auto-replies should not be created or modified in the 24 hours before migration, or mail loops and lost settings will occur.
  3. Folders on ACS that match standard Exchange folder names will be appended with “from-ACS” to avoid any issues caused by duplicate names. So, for example, “Drafts” on ACS will be renamed to “Drafts-from-ACS” on Exchange.
  4. Messages stored in “Drafts-from-ACS” will not be editable unless they are moved to the Exchange “Drafts” folder.
  5. Folders called “sent” will get moved to “sent-from-ACS” and will not be merged with the default Exchange folder called “Sent Items.”
  6. Email messages that were flagged in ACS may lose that flagged designation when they are moved to Exchange.
  7. Messages that were flagged as “deleted” prior to migration, but were not purged, could end up in the Inbox as active and could need to be marked for deletion again.
  8. Messages may lose their sort order and could need to be resorted (e.g. by date, newest to oldest) after the migration.
  9. It has been observed, particularly in Outlook 2011, that some migrated messages may transfer with modified date or time stamps.
  10. Sometimes email attachments sent by Thunderbird (PC and Mac) do not display correctly in Exchange and may cause the migration to fail. To resolve this, you should either (a) delete the message and make sure Trash is emptied or (b) drag the message to a local folder (and delete it from ACS).
  11. When switching from ACS to Exchange in the same email client, particularly in Outlook, it has been observed that some messages may get moved to the Junk Mail folder. If that happens, you can simply drag them out of Junk Mail into the correct folder.
  12. Mail storage requirements for the migrated messages will be lower on Exchange than they were on ACS because Exchange handles the storage of header and message text in a more compressed way.
  13. After migration and transition to full Exchange, your email clients will present your name in the format Last, First Middle and you might, for example, lose your Nickname. However, as needed, you can Change How Your Name Appears.

Device clients only:

  1. Messages flagged on a device will not sync back to the server when the device is still configured to use ACS. Flagging will work once the device has been configured to use Exchange.
  2. Blackberry and iOS devices save Drafts and Sent Messages locally (on the device) and not to a folder on the server. As a result, migrated messages do not appear in OWA or in any desktop client, just as they did not appear previously in Horde or any desktop client. Messages will remain on the device after the transition from ACS for as long as the account is still set up to access acs-imap. However, once the account is switched over to access the Exchange account directly, those Drafts and Sent Messages will be lost unless you follow the steps outlined below.
Forward any Drafts or Sent Messages that you want to keep to your address so they will be preserved in your Inbox when you reconfigure the Blackberry to access Exchange.
Apple iOS:
Change the default Mail settings for Drafts and Sent Messages in order to pick folders that are on the Server. This change will preserve the contents of those folders when you reconfigure your iOS device to access Exchange.