The question is often asked if Shared Mailboxes can be put into a 2 way continuous synchronisation throughout the duration of migration to allow both migrated & non-migrated users access to the same Shared mailbox with the same content and to be able to function from both systems at the same time.
This is not possible using the Quest/Dell Software toolset for mailbox synchronisation and migration. There can only be one ‘live’ instance of a Shared Mailbox, either on the legacy or the target messaging system. Not both, Not ever.
The recommended approach from Quest/Dell Software is to migrate Shared Mailboxes together with the user mailbox migrations. The preferred approach is to switch the Shared Mailbox at the same time as the key users of the shared mailbox, else leave it in legacy until the last user is across to the target platform.
If using the Sync & Switch method for Shared Mailboxes the following will apply:
Shared Mailbox still live on Legacy Platform
Legacy Users continue to have access exactly as today
Target Messaging service users can see the target copy of the Shared Mailbox (Outlook 2010/2013 automatically add in all Shared Mailbox a user has permissions too – whether migrated or not), users can:
- Read items & Reply from the Shared Mailbox
- The Read status & Replies will NOT synchronise back to the live Shared Mailbox in legacy
- New email items will only appear during the next synchronisation pass (which could be a delay of minutes to hours)
In this situation end users already switched to the Target Messaging system often mistakenly think that the Shared Mailbox is fully functional as they can see it and may see new items periodically updating.
Shared Mailbox switched to and now live on Target Platform
Legacy Users will still have access to the legacy Shared Mailbox contents as they were prior to the switch, however no new emails will appear and they will be unable to reply to old email (they will only be able to forward email internally). All new email will have been re-directed to the target Shared Mailbox as part of the mailbox switch
Target Users have access to the migrated target Shared Mailbox exactly as they did in legacy but now with all the full functionality. Users will be able:
- Read and Reply to all emails, both internal and external
- Organise folders as needed
- New emails will appear immediately in the Inbox, bypassing the legacy Shared Mailbox
If using the Remote Collection method for migration any Shared Mailbox content can only be live and valid on either the source or target messaging system, not both, which means the target Shared Mailbox will be empty until the Remote Collection migration is triggered. Once that is triggered the legacy Shared Mailbox is no longer useful as it loses functionality.
Real advice, Real Experience
I often make a judgement call on switching Shared mailboxes, I advise customers to switch them once the key users who need access to it are switched. You can use Quest/Dell Software Reporter or a PowerShell script to list out all Shared Mailboxes and who has rights to them. It is then a case of identifying and contacting Shared Mailbox owners and agreeing a plan of action. Communication is important here, set the expectations clearly and you will have a smoother ride. Don’t second guess when it should be switched.