Microsoft throttles connections and bandwidth usage to their cloud service – Office 365.
There are some steps that can be taken to improve the throughput and performance when migrating to Office 365. These are described in this section. In addition it is recommended that Microsoft be contacted and a request made to increase the throttling limits whilst the data migration is being undertaken.

Mailbox or Personal Archive

Whilst planning your Office 365 migration, it’s important to discuss if you are migrating to either a mailbox or a personal archive. If you’re migrating to a personal archive, this must be enabled previously to your migration.

Remember that there might be different size and item limits on either choice.

Item Size Limits

There may be size limits set by Microsoft on your mailboxes when being ingested into Office 365. For more information on this, including how to increase mailbox size limits, click here.


There are two methods of authentication when using Archive Shuttle; oAuth (recommended) and Basic authentication.

For more on oAuth, click here. This includes authentication using a certificate and/or a secret.

For more on Basic authentication, click here. This is using the account UPN and password in the credential editor.


You may need to lift throttling restrictions for your project. Restrictions are set by Microsoft, but lifting them for a set period of time (30, 60 or 90 days) is a straight forward process. Check out more on this here.

Journal Transformation/Journal Splitting

Migrating journals requires thought on whether you would like to process them as journal transformation, or journal splitting. For more on this, click here.


Migrating leavers to Office 365 takes further consideration. For more on this, click here.

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3 Replies to “Planning for Office 365 Migrations”

  1. This page is pretty anemic IMHO and really speaks to a single issue when migrating to o365. Perhaps links to other relevant areas or some more content of value could be added.