Migration to Office 365/Exchange Online

I recently had a chance to help a small business move their 70 mailboxes to the Exchange Online service. This company was running Windows 2008 with Exchange 2007 on premises installation and we helped them migrate to Office 365/Exchange Online over a couple weekends. During the migration we ran into several issues. I couldn’t find many online resources where people documented these errors, so I wanted to write them down on this site.

Issue #1
Symptoms:
Outlook Anywhere (RPC over HTTPS) service was configured, running and available to end users. However we received various errors when trying to establish a migration endpoint. Even though the service was working, the Remote Connectivity Analyzer (https://testconnectivity.microsoft.com/) was failing on Outlook Anywhere tests.
Resolution:
Looking around online, we thought the issue was related to the Exchange 2007 service pack level, so we upgraded to SP3. I’m not sure if this actually helped, but I figured it was worth mentioning as it may have fixed other issues we could have seen during the migration. The actual fix for this issue (and unfortunately I can’t find the Office 365 communities post where we found the suggestion) was to create a hosts file entry on the exchange server containing the IP, server name and FQDN of the internal Exchange server name. DNS was working perfectly, so I’m not sure why this was needed. However, after the entry was added the Remote Connectivity Analyzer tests started working and we were able to move forward with the migration.

Issue #2
Symptoms:
Batch loaded into Office 365 environment to begin migration, but after several hours the task fails
Error log may mention “MigrationPermanentException: Error: MapiExceptionLogonFailed: Unable to make connection to the server”
Resolution:
Verify permissions, specifically Receive-As rights to the database (http://community.office365.com/en-us/forums/158/t/18911.aspx).

Add-ADPermission -Identity "Mailbox Store" -User "Trusted User" -ExtendedRights Receive-As

Issue #3
Symptoms:
When opening Outlook as a user when the PC is joined to the domain, the on premises mailbox is opened instead of the Office 365 mailbox. When using a non-domain joined test PC, the Office 365 mailbox was opened.
Resolution:
This was caused by the way Exchange handles autodiscover. You can read more about the process here: http://msdn.microsoft.com/en-us/library/office/jj900169(v=exchg.150).aspx. We found a pair of scripts (ExportO365UserInfo.ps1 and Exchange2007MBtoMEU.ps1) available here: http://community.office365.com/en-us/wikis/exchange/845.aspx which allow you to convert the users active directory account into a mail enabled user that references Office 365 instead of a mailbox user in the on premises install.

This was my first experience with Office 365/Exchange Online. I was surprised at how complicated some of the migration steps were. With the whole ‘cloud-based’ self service model, I assumed that the migration path would be just a few clicks. With the handful of lessons learned from going through this process once, I would feel more comfortable doing another migration (but its not something I would volunteer for). I hope someone finds this post helpful.