Litigation Hold Migrations

We do support Litigation Hold migrations, but with some important known limitations.

​Be aware of these limitations since, for obvious reasons, Litigation Hold tends to have a 100% fidelity requirement. ​

All emails in the primary mailbox will indeed be migratedMigrationWiz is unable to migrate Litigation Hold data from the Archive Mailbox. If Litigation Hold data is in the Archive Mailbox, it must be moved to either the primary mailbox or the Recoverable Items.

Folders created in Litigation Hold are considered to be "email folders" but this is not necessarily the case. Therefore, all the special Litigation Hold items (whose type is not email) fail to migrate due to a known limitation in EWS (which is what MigrationWiz uses for migrations, when migrating from Exchange 2007+ as the source).

Several of these are considered to be email folders by EWS, even though they are not. Due to a bug in EWS, if you try to create a non-email item within those folders, it reports an error stating: "the item type does not match the folder type".

For example, if a contact is deleted, it will be stored in the /Purges folder. When we try to migrate this contact to the destination mailbox's /Purges folder, it reports an error.

Here are some known folders in the recoverable items mailbox:

  • Versions: If Litigation Hold (or for that matter, In-Place or single item recovery) is enabled, this subfolder contains the original and modified copies of the deleted items. Note: This folder is not visible to end users.
  • Purges: If either Litigation Hold (or single item recovery) is enabled, this subfolder contains all items that are hard-deleted. Note: This folder is not visible to end users.
  • Discovery Holds: If In-Place Hold is enabled, this subfolder contains all items that meet the hold query parameters and are hard-deleted.
  • Audits: If mailbox audit logging is enabled for a mailbox, this subfolder contains the audit log entries. This folder is not migrated with MigrationWiz.
  • Calendar Logging: This subfolder contains calendar changes that occur within a mailbox. This folder is not available to users.
  • Deletions: This subfolder contains all items deleted from the Deleted Items folder. (In Outlook, a user can soft-delete an item by pressing Shift+Delete.) This subfolder is exposed to users through the Recover Deleted Items feature in Outlook and Outlook on the web.

The folders indicated above will, by default, be migrated into a folder at the Destination, named "Deletions". Any mail items within these folders will be migrated. The non-email items will return an error in the MigrationWiz portal, but will not prevent the migration from completing. Typically there are only a few extra errors caused when performing Litigation Hold migrations (since most items in these folders are, in fact, email items) so the error count threshold will not need to be adjusted.

The migration process includes a folder discovery, plus it attempts to retrieve items from within each folder. If the attempts fail, this folder will be excluded during the migration, so that the migration can continue.

If you prefer to have the folders in the recoverable items mailbox migrated into their own corresponding folders at the Destination, and not migrated into a folder named "Deletions", you must add the Advanced Option (under the support section): OverrideRecoverableItemsFolderMapping=1 to your project before performing your migration.

Here are the recommended step-by-step directions for performing a migration that includes mailboxes set for Litigation Hold:

  1. Create a regular mailbox migration project, set the advanced options and submit mailboxes for migration. Follow directions under the migration guide for the appropriate scenario. All migration guides can be found in the MigrationWiz category of the BitTitan Help Center.
  2. Once the mailbox migrations have completed, create a new mailbox migration project specifically for Litigation Hold.
  3. Set the project advanced options for this Litigation Hold project, so that the Source: Migrate from: parameter is set to Recoverable Items. This will automatically set the Destination: Migrate to: parameter to be set to Recoverable Items.
  4. Return to the regular mailbox migration project dashboard, select completed migrated items, and move these items to the Litigation Hold project.
  5. Now, from the Litigation Hold project, submit items for migration. These will then migrate all items under the recoverable items folder at the source into the recoverable items folder at the destination.
  6. Once complete, move items back to the regular mailbox migration project.
  7. All emails will be migrated.
  8. Users will not be able to see anything that they should not be able to see.
  9. Mailbox migrations allow up to 10 passes per mailbox. Therefore, migrating mailboxes under the Litigation Hold project will not consume any additional licenses, provided that the items were moved between projects.
  10. Do not add new mailboxes under the Litigation Hold project. Instead, move items into this project. This way all project statistics and license history will be retained.​
  11. When migrating to recoverable options, it is recommended to increase the retention period for deleted items folder. The default retention period is 14 days. This should be increased to the maximum, which is 30 days. Steps for this are included in this TechNet article:


Migrating Litigation Hold Data for Inactive Users

By default, mailboxes for inactive users with litigation hold are not migrated by MigrationWiz®. Because the users are not licensed in the destination system, the mailboxes are not created, and the held items do not have a location to be migrated to.

It is possible to set up a migration specifically to migrate these held mailboxes. Use the steps below to create a project and migrate litigation hold data for inactive users in an Office 365 to
Office 365 tenant migration scenario:

  1. Find all inactive mailboxes. This can be done using the Powershell command below.
    Get-Mailbox -InactiveMailboxOnly -ResultSize Unlimited
  2. Add inactive users to MSPComplete either individually (Quick Add) or using a CSV (Bulk Add). 
  3. Create the target mailboxes in the destination Office 365 tenant.
  4. Add licenses to the newly created mailboxes in Office 365. (This requires at least an E3 license.)
  5. Set litigation hold on the new mailboxes.
  6. Set all the new mailboxes as Inactive. This will also remove the Office 365 license from those mailboxes.
  7. Create a new MigrationWiz Mailbox project.
  8. Do not check the box for Tenant to Tenant Coexistence.
  9. Click Save Project.
  10. Add the email addresses for the inactive users to the project. The source email addresses must match the inactive mailbox UPNs. The destination email addresses should be the newly created email addresses that were created earlier in these steps. 
  11. Once the project is created, click Edit Project and select Advanced Options.
  12. Under both the Source and Destination sections, click Recoverable Items.
  13. Click Save.

The migration is now ready to be run. Other changes can be made if your scenario requires them, but no other settings are required to migrate mailboxes for inactive users.

If this migration fails, recover the inactive mailboxes before retrying the migration of the Recoverable Items.  Use the steps in this Microsoft document to recover the mailboxes: Recover an inactive mailbox in Office 365, then run the migration again when the mailboxes are recovered.


Litigation Hold vs. In-Place Hold

Litigation Hold migration involves putting a user's entire mailbox on hold for the purpose of retaining it for legal review.

In-Place Hold migration involves putting a subset of a user's entire mailbox on hold for the purpose of retaining only certain types of email.

The only difference between these two types of migration is a query. Litigation Hold can be enabled to hold all items that are deleted or modified. In-Place Hold is set up like Litigation Hold, but adds a filter query to only retain specific kinds of email.

Litigation Hold works like this:

In the normal deleted item workflow, a mailbox item is moved to the Deletions subfolder in the Recoverable Items folder when a user permanently deletes it, or deletes it from the Deleted Items folder. A deletion policy (which is a retention tag configured with a Delete retention action) also moves items to the Deletions subfolder when the retention period expires. When a user purges an item in the Recoverable Items folder, or when the deleted item retention period expires for an item, it is moved to the Purges subfolder in the Recoverable Items folder and marked for permanent deletion. It will be purged from Exchange the next time the mailbox is processed by the Managed Folder Assistant (MFA).

When a mailbox is placed on Litigation Hold, items in the Purges subfolder are preserved for the hold duration specified by the Litigation Hold. The hold duration is calculated from the original date an item was received or created, and defines how long items in the Purges subfolder are held. When the hold duration expires for an item in the Purges subfolder, the item is marked for permanent deletion and will be purged from Exchange the next time the mailbox is processed by the MFA.  If an indefinite hold is placed on a mailbox, items will never be purged from the Purges subfolder.

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