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EML to Office 365 Migration Guide

Last Update: 7/21/2017 11:34 AM
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​​EML to Office 365 Migration Guide

Important: When you sign in to MigrationWiz, you are redirected to the Getting Started page in MSPComplete. To get to a migration project created before April 4, 2017, click the Go to Projects button on the Getting Started Page. To create a new project for the migration scenario documented in this article, click the waffle icon (waffle.png) in the top navigation bar of MSPComplete, and select the appropriate migration product.


  • This is the complete onboarding task flow for migrating EML files to Office 365 mailboxes.
  • Complete each step in order. Links to corresponding Knowledge Base articles are provided.
  • If you are migrating to Office 365 archives rather than mailboxes, the steps will be exactly the same, but the Destination will need to be set to Archives. This is set under MigrationWiz Project Advanced Options > Destination: Microsoft Office 365 > ArchivesKB004910

Prepare the Azure Environment and upload EML files to Azure

  1. Estimate Azure storage costs. This step is optional, but is useful in order to provide the customer with upfront storage costs ahead of time.  KB005177
  2. Buy an Azure subscription (or use the free one-month trial, and be aware that this option is only viable if you are performing a very small migration).  KB004996

  3. Create an Azure storage account, and take note of the Storage Account Name and the Primary Access Key. (In Azure, from the storage screen, click on Manage Access Keys at the bottom of the screen.) The Storage Account Name and the Primary Access Key need to be entered into the MigrationWiz document project when specifying the Source settings. We recommend that you create an Azure Storage Account in the same Microsoft data center as the Destination Office 365 tenant. KB004832

  4. Create a public Azure container (e.g., migrationwiz). Note: You will be prompted to enter this container name when creating your MigrationWiz project. KB008059​

  5. Ensure that the EML file structure follows supported formats. KB005890

  6. Upload the EML files to your Azure container. Options include UploaderWiz, AZCopy, Azure Storage Explorer, Microsoft Azure Import/Export Service and PowerShell. Details can be found in KB004931.

    • Notes:

    • If using you are using UploaderWiz for the upload to Azure, this includes logic to overcome Microsoft restrictions to Azure container names. KB005484

    • UploaderWiz can only support file path names that are shorter than 248 characters. This limitation is due to the Microsoft .Net Framework.KB005516

Prepare the Destination Environment

  1. Create an administrator account in Office 365 to be used for migration, or use the global admin account for the tenant. KB004948

  2. Set up accounts on Office 365 and assign licenses. These can be created in several ways:

MSPComplete Steps (

  1. Create the customer. KB005421
  2. Create the Source and Destination endpoints.

    • For the Source endpoint:
      • Click on EndPoints > Add Endpoint > Enter endpoint name > For endpoint type, select EML (Block Storage).
      • Enter Storage Account Name and Access Key in the fields provided.
    • For the Destination endpoint:
      • Click on EndPoints > Add Endpoint > Enter endpoint name > For endpoint type, select Office 365 > fill in the required fields.
  3. Launch a Personal Archive migration project. Select All Products > Personal Archive Migration.

MigrationWiz Steps

  1. Set up the Project. Create project > Create a personal archive project > Name the project > Select MSPComplete customer > Select the Source endpoint (enter the Container Name in the field provided) > Select the Destination endpoint.
  2. Set the Project Advanced Options.  KB004834
    • The following options are the most valuable for this migration scenario:
      • Set the Preferred BitTitan Data Center. For the fastest migration speeds, select the data center that is closest to your Office 365 Destination tenant.  KB004268
  3. Add items to MigrationWiz project.We recommend that you use the Bulk Add feature to do this. Select Add > Bulk Add > fill in the columns labeled Source Email (the names of the EML files in your Azure container; typically they will be in SMTP email format), and Destination Email.
  4. Set the Destination mailbox to ingest each file. Click on the Edit Item (pencil icon) to the right of the row. Under the Destination Email Address field, enter the mailbox that this file will be ingested into. KB004937
  5. Run Verify Credentials. KB004511
  6. Purchase MigrationWiz-Personal Archive licenses. KB004647
  7. Perform a Full Migration pass.  Checkmark the box next to the Root Path > Select the Start button from the drop-down list > Select Full Migration > Click on the Start Migration buttonKB004938
  8. Run Retry ErrorsKB004658
  9. If problems persist, contact Support. KB004529
  10. Click on the pie chart icon in the MigrationWiz dashboard to receive an email containing all the project migration statistics. KB004626