Help! We need to migrate to Office 365, but can’t use the standard Microsoft migration tool.
Normally you’d migrate from an on-premises Exchange to an Office 365 tenant that you either control, or have integrated into your environment via Azure Active Directory Connect (AADC). If you have that capability, the email migration is straightforward. But what if you don’t have an integration point? What if you’re being acquired (or performing an acquisition) and you don’t want to (or can’t) use AADC to permit Exchange on-premises to be placed into a hybrid configuration and do a conventional migration? And of course, there’s no Microsoft solution for migrating Teams and OneDrive.
This situation calls for a 3rd party solution. Enter: BitTitan.
Exchange Email Migrations
BitTitan allows you to migrate from Exchange on-premises (version 2007 upwards), without any integration points. You need two accounts; one in the source Exchange and one in the Office 365 tenant. You have two options for the migration; Impersonation or Delegate access. To read more about these two options, click here. BitTitan recommends using impersonation, but their default is delegate access. Impersonation is recommended because it permits the migration of more mailboxes at once (concurrency speeds the migration) and does not have the same impact when throttling is imposed at the destination.
BitTitan requires a paid license per user but the time saved by using a migration tool is more than worth it when you consider one alternative: using PST files to export and import data.
BitTitan will migrate almost everything from an Exchange source, including Contacts, Calendars, Notes, Rules, etc. However, it works as a migration tool and not as a synchronization tool. This means that if a user changes an item (e.g. a contact or an appointment), the change will not be sent to the destination.
So BitTitan resolves the issue by sending only email items when it prepares a mailbox, or pre-staging, as BitTitan calls it. When the final migration takes place, that’s when all non-email folders come over. When a final migration is executed that’s when you have to change the users’ profile so they can’t use their old mailbox and are thus not tempted to add or change anything in the old mailboxes. The number of items in the Calendar and Contacts folder is typically very small compared to typical email folders, so users will likely not notice the few minutes while they are setting up their profile when the appointments are migrating.
When performing a hybrid Exchange migration, the OST file is reused. This is not the case in a BitTitan migration. Take care to remove the old OST while the new one is being populated if you think there may be capacity problems at the device end.
If you’re performing a migration that, for example, takes several Exchange mailboxes and puts them all into a single Office 365 shared mailbox, you can use some commands in the advanced section of either the ‘project’ (as BitTitan calls them), or on individual items (i.e. mailboxes) inside the project to direct a number of source mailboxes into a folder/subfolder structure within a shared mailbox.
OneDrive Migrations
BitTitan will move OneDrive to OneDrive so all the user documents can be moved from source to destination. However, some ‘gotchas’ are lying in wait for you.
Firstly, make sure the users’ devices are logged into OneDrive. Often, users are correctly saving to their OneDrive folder on their PC, but the app is not logged into OneDrive, so the new and edit documents are not getting into Office 365.
Secondly, don’t allow the customer to postpone the migration once started. As with email, you can pre-stage documents, but once that document has been sent to the destination, it won’t be updated if it gets changed. Do not execute pre-stage migrations for items that are very new and, if at all possible, ensure users create a new document (through Save-As, for example) if they must make a change during this migration period. As you can see, it’s important to keep migration timeframes down to days rather than weeks. In addition, BitTitan suggests you turn off versioning in the destination for the duration of the migration.
There is also the issue of space—as with email migrations. Until recently all OneDrive items were synched to the local PC. That’s no longer the default, which is only to synch the metadata and recently-used files. This saves space on the device. However, if that is not the case you will have the situation where the old fully populated OneDrive folder and the sparse new one in the new tenant are side by side; potentially twice the space if a user chooses to download their entire OneDrive contents. Audit the user’s device to ensure you don’t run out of space. Delete the old OneDrive folder as soon as you’re sure data has been correctly migrated.
As in the case of mailbox migrations, there exists the possibility to take multiple OneDrive accounts and divert them into a folder/subfolder structure if you have terminated users at the source whose data will be required for a period of time. Remember that the destination account does need to be licensed; only shared mailboxes don’t need a license. More importantly, the commands to move items into a folder/subfolder structure are slightly different than those used to move email folders. Consult the BitTitan documentation to find the correct syntax for your needs.
Final Notes
Follow the migration guides carefully. They have been very well written and are proscriptive. There isn’t much of an opportunity to go ‘off-piste’ and freewheel it. We’ve have had to raise a case to get advice on syntax a couple of times. In one case, this was to troubleshoot a destination configuration which made no sense to the history of the target tenant, but which was resolved by entering an advanced support text string into the project.
We at Anexinet have had a lot of success with BitTitan, and highly recommend it for Office 365 migrations. To learn more, please contact us. We’d be happy to perform the migration for you, freeing-up your team to focus on more important aspects of the project.

Mark Arnold
Microsoft Architect