Step by step Office 365 to Office 365 – Email Migration

The step by step Office 365 to Office 365 migration guide is up. This isn’t as straightforward as one’d wish. When you first register a domain to an Azure Tenant, you cannot register it in another Tenant. This is understandable from a logical standpoint, but who better than Microsoft to make tools for you to easily move to a new tenant? Apparently, even Microsoft advises you to use third party tools.

As stated in the article, there are some steps, and there will be downtime. Not long downtime, but be sure to be prepared.

Also, if you’re an incredibly small company, you could always do PST-migration. I wouldn’t recommend this if you’re above 10 users, it takes time and is a hassle. 

Let’s get started!

Step by step Office 365 to Office 365 – Migrationtools

This Step by step Office 365 to Office 365 migration guide will help you from start to finish.

We looked at MigrationWiz from Bittitan and Dell On-Demand Migration. The Dell product is just renamed from Quest Software (Which was an awesome company, no wonder they got bought).

  • The service they provide is pretty much the same, and both will do the job correctly.
  • The pricing for MigrationWiz was $11.99 USD per mailbox, while Dell On Demand cost us $9.4 USD per mailbox/month.
  • MigrationWiz has documentation and great wikis, while Dell On Demand is a nightmare. I still haven’t found any documentation…it’s crazy.
  • Dell On Demand is provided by..well, Dell and therefore you don’t need a Credit Card, and can buy it through a partner.

We ended up choosing Dell because of the lower price, the same service and the fact that you can buy it from a reseller/distributor. It’s just a shame I still can’t find any (good) documentation, but that’s besides the point. We’re going to make our own!

Pre-Requisites

  • In the “Old” tenant (Source tenant), log on as an admin on the Exchange Online Admin Center
  • Go to Permissions, Discovery Management:Step by step Office 365 to Office 365
  • Open Discovery Management, Add Impersonation Rights and add yourself as a member

Step by step Office 365 to Office 365

  • Do the same for the new tenant (target tenant)
  • Now you need the list of all recipients in your old tenant (Source tenant), export to CSV from Recipients -> Mailboxes, Resources, Contacts and Shared. Step by step Office 365 to Office 365
  • Be sure to check “Email Address”Step by step Office 365 to Office 365
  • We need to make some changes to the exported CSV. Since we’re migrating from O365 to O365, we need to make sure both tenants, TARGET and SOURCE, use the *.onmicrosoft addresses. This is quite important.
  • Step by step Office 365 to Office 365
  • Log on to the source tenant via Azure Active Directory Module for Powershell, and type in this Powershell code. This is just to get an overview of what we’re dealing with, how many mailboxes, what’s the total size, etc.
Get-Mailbox –resultsize unlimited | Get-MailboxStatistics | Select DisplayName,StorageLimitStatu
s,@{name="TotalItemSize (MB)";expression={[math]::Round(($_.TotalItemSize.tostring().Split("(")[1].Split(" ")[0].Replace
(",","")/1MB),2)}},@{name="TotalDeletedItemSize (MB)";expression={[math]::Round(($_.TotalDeletedItemSize.tostring().Spli
t("(")[1].Split(" ")[0].Replace(",","")/1MB),2)}},ItemCount,DeletedItemCount | Sort "TotalItemSize (MB)" -Descending | E
xport-CSV "C:\Temp\MailboxSizes.csv" -NoTypeInformation
  • Before we go to the migration tool, we need to create all the users we want to migrate in our new [TARGET] tenant. You can grab all the information you need from your [SOURCE] tenant via Azure Active Directory Powershell. Example below, use the same CSV-file to create new users in bulk with Powershell
Get-MsolUser | Select-Object UserPrincipalName,DisplayName,Department,Country,City,isLicensed,Fi
rstName,LastName,Office | Export-Csv c:\temp\Company\CompanyUsers.csv

Configuring

  • Sign up for a new account by going here, and click on either Try Online, or Buy Online.

Step by step Office 365 to Office 365

You’ll be required to register. Go through the whole ordeal, and activate your E-mail when you’re finished.

Migration
  • Now you’ll be greeted by this page. Simple enough, eh? Step by step Office 365 to Office 365
Dell On-Demand Migration – Connections
  1. Start with Connections. Type in administrator accounts with impersonation rights as both the [SOURCE] and [TARGET] connections. Be sure that you choose the old tenant as Source, and new tenant as target. Step by step Office 365 to Office 365
  2. Click Test connection on both sides. If you have impersonation rights correctly set up, these should be completely fine. Step by step Office 365 to Office 365

Let’s move on

Dell On-Demand Migration – Mailboxes

Step by step Office 365 to Office 365

  1. Remember the “Export to CSV” of our mailboxes? This is going to come in handy now. Remember that you might want to bring other types of mailboxes into the mix (Shared Mailboxes for example).
  2. We’re not going to type in all of these mailboxes, they might be in the thousands! Let’s grab the TSV Example file and modify itStep by step Office 365 to Office 365Step by step Office 365 to Office 365
  3. Import the file and click Continue
Dell On-Demand Migration – Options

These are pretty self-explanatory. I might update this part with a deeper explanation after a while though. For now, let’s just leave it as is, since we want everything to sync and we don’t want to put stuff in OneDrive for example.

Step by step Office 365 to Office 365Step by step Office 365 to Office 365Step by step Office 365 to Office 365

Dell On-Demand Migration – Migrate

You’re basically done! The migration is ready and you can start migrating all your mailboxes. Step by step Office 365 to Office 365I deeply recommend letting the migration process finish before you change MX-pointers, but we’ve created the possibility to do that whenever we want. The migrationtool is using *.onmicrosoft.com usernames, and not the accepted domain for the user.

Post-Migration activities

Now is the time to cleanup the old tenant and import your domain to the new tenant.

We need to remove the domain from the [SOURCE] tenant, replace contoso.onmicrosoft.com to your tenantname.onmicrosoft.com in the following code.

Get-MsolUser | Where { -Not $_.UserPrincipalName.ToLower().StartsWith("admin@") } | ForEach { Set-MsolUserPrincipalName -ObjectId $_.ObjectId -NewUserPrincipalName ($_.UserPrincipalName.Split("@")[0] + "@contoso.onmicrosoft.com")}

Now you may remove the domain from Office 365.

Click on Waffle-Menu to your upper left, and then Admin

Go to Domains

Step by step Office 365 to Office 365

Click on the domain you want removed, and click Remove DomainStep by step Office 365 to Office 365

On your new [TARGET] tenant, add the domain, verify it, and remember to choose Office 365 services such as Exchange Online

Remember to update the UPN and aliases with your previous domain, or a new one.

That’s it! We’re done with Step by step Office 365 to Office 365 email migration. This is part of a series on how to migrate your company to Azure/Office365/Enterprise Mobility. Check for more

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