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Summary: Bulk mailbox migration to Office 365 is a technical task and may feel complex for both novices and tech-experts. In this article, we’ve discussed all its stages and the step-by-step process to migrate mailbox to Office 365. Instead, you can use our Kernel Office 365 Migration tool to escape the manual hassle and limitations.
With growing demand for a secure, scalable, accessible, and productive email environment, businesses started relying on Office 365. The features like cloud-based storage, higher security, smooth access, etc., are the center of attention for businesses. Since they can’t leave their data behind in on-premises Exchange server, the need for mailbox migration to Office 365 became primary.
Migrating the on-premises email system also carries real business risks, like data loss, user downtime, mail flow disruption, security breaches, etc. These issues become even more severe when planning for a bulk mail migration because a single mistake can affect the entire organization’s workflow.
This guide explains how to manage bulk mailbox migration to Office 365 effectively with step-by-step guidance. Join your hand with us, let’s make the bulk mailbox migration to Office 365 free from risks.
Why Migrate Mailbox to Office 365?
Mailbox migration to Office 365 offers many benefits to businesses/individuals. A few common ones are:
- Remote accessibility.
- Cloud-based storage.
- No server or maintenance cost.
- High security and compliance.
- Auto updates with zero maintenance downtime.
- Integration with applications like Teams, OneDrive, SharePoint, etc.
Apart from the benefits, the bulk mailbox migration to Office 365 should be effortless and secure.
Facts to Know Before Bulk Mailbox Migration to Microsoft 365
Before migrating bulk mailbox to Office 365 manually, consider the below factors:
- The bulk mailbox migration takes enough time, depending on the mailbox size and quantity. Once done, the organization can access and manage the user account in Microsoft 365.
- Using cutover mailbox migration methods makes the process simple and efficient; it is recommended to migrate only 150 mailboxes at a time.
- Your on-premises primary domain must be added and verified as a custom domain in the M365 tenant. Also, it should be configured as an Accepted Domain on both on-premises and Exchange Online.
- Open TCP ports 6001,6001 and 6004 on the Exchange 2003 for connectivity between the servers.
- Once the mailbox migration to Office 365 completes, the assignment of licenses to every user is necessary to activate those cloud mailboxes.
How to Perform Bulk Mailbox Migration to Office 365?
Here is a complete step-by-step process for bulk mailbox migration to Office 365. Follow the below steps carefully to migrate mailbox to Office 365 without interruption:
Stage 1. Preparation Before Migration Procedure
Before going further in bulk mailbox migration, make the changes as guided below:
- Before going further in cutover migration, first make changes in the Exchange Server environment. Also use Powershell and turn off the directory synchronization before preceding.
- Configure Outlook on your on-premises Exchange Server and use a certificate issued by a trusted certification authority to execute cutover migration
- Establish a connection to your Exchange organization via Outlook Anywhere with available options.
- Set up Mailbox Replication Service (MRSProxy) on your on-premises Exchange Server.
- Provides all necessary permissions to on-premises Exchange Administrator accounts to access and migrate mailboxes to Office 365.
- Make sure that all mailboxes are visible from the address list before migration.
- Turn on Cloud Voicemail for users after disabling the Unified Messaging (UM) for on-premises mailboxes.
- Also don’t forget to create a mail-enabled security group in Office 365 before starting the migration process.
Stage 2. Begin Bulk Mailbox Migration
We have mentioned several simplified steps to help you to migrate bulk mailboxes to Office 365.
Step 1. Check the Ownership of Domain
At the very first, we have to check the ownership of the on-premise domain. Here are the sub-steps to follow:
- Log in to your Microsoft 365 account, click on Admin, and access Microsoft 365 admin center.
- Click on the Domains option in the Settings dropdown, and tap on +Add domain.
- Enter the on-premise Exchange server domain name and click on Use this domain option.
- Select Add a TXT record to the domain’s DNS record and tap on Continue.
Note: You can also select the other available option at your convenience.
- Add the given TXT record to your domain’s registrar or DNS hosting provider. Tap on Verify.
- Once verification is done, click Finish.
Step 2. Connect Office 365 and Email System
A migration endpoint builds a connection between on-premises servers and Office 365 for migration. Here are the sub-steps to follow:
- Go to EAC, tap on migration, then click on Endpoints.
- Click on Add to create a new migration endpoint.
- Enter the details as required.
- Select Outlook Anywhere and input Migration endpoint name.
- Provide the domain\username and type Email address of the account.
- Input the RPC proxy server for Outlook Anywhere.
- Once the above guides are performed, tap on Create.
Step 3. Set up a New Cutover Migration Batch
Follow the sub-steps below to create the cutover migration batch.
- Go to EAC and tap on Migration, then click Add migration batch.
- Input the migration batch name and select the mailbox path. Click Next.
- Select Cutover migration as the migration type. Click Next.
- Make sure that all the prerequisites are fulfilled before migration. Click Next.
- Select the migration endpoint using the drop-down. Click Next.
- Select the start and end time for the migration by Schedule batch migration
- Tap on Save to create the migration. Click Done.
Step 4. Start the Cutover Migration Batch
Follow the below sub-steps to resume the migration batch:
- Go to the EAC and tap on Migration.
- Select the batch from the available list, tap Resume migration, and confirm the pop-up message.
- Migration batch status changes to Starting once started.
Step 5. Map Emails to Office 365
Emails use MX records to decide where to send emails before/during the migration process. When the migration completes, change the MX records to Office 365 to make sure that all emails are sent to Office 365 mailboxes. However, it also helps you stop your old email system after migration to the new environment.
Step 6. Remove the Cutover Migration Batch
Once MX records are changed successfully, verify that all emails are routed to Office 365. Now, notify the users that their mail is going to Office 365 and check the following points before removing the migration batch:
- The selected bulk mailboxes have been migrated, and users have started using Office 365 mailboxes.
- Office 365 mailboxes must be synchronized at least once.
Now, follow the steps below to delete the cutover migration batch:
- Go to the Exchange Admin Centre and click on the Migration.
- Select the migration batch and tap on Delete.
- Click Yes in the confirmation pop-up.
Migration batch is successfully deleted.
Note: Once bulk mailbox migration completes, assign the license to the user accounts to activate them. If you don’t assign a license, the mailbox will be disabled after the grace period (30 days).
Stage 3. Finish the Post-Migration Tasks
In this stage, there are a few post-migration tasks you need to complete. They are:
- Set up an Autodiscover DNS record so users can easily connect to their new Office 365 mailboxes.
- Deactivate it when you find emails are routed to Office 365, and you don’t want to continue your on-premises Exchange server.
Limitations of Manual Mailbox Migration to Office 365
- Microsoft limits the simultaneous mailbox migration (default 20)
- Limits the number of items and message size.
- Rules, calendars, and contacts don’t always transfer perfectly.
- Consecutive steps are error-prone.
Apart from the reliability of the manual approach, these limitations sometimes make the migration unreliable. To make the bulk mailbox migration to Office 365 process easy and effective beyond limitations, use the professional solution instantly.
Try Out Reliable Solution: Kernel Office 365 Migration
You can migrate a mailbox to Office 365 manually if you’re a technical expert and you have the potential to bear its limitations. If you want to avoid the hassle, switch to a professional Office 365 migration tool.
Kernel Office 365 Migration is one of the best tools that helps to migrate bulk mailboxes to Office 365 effectively. It escapes all the manual hassle and limitations and migrates the Office 365 mailbox smoothly. It comes with advanced data sorting filters to perform the precise migration process with more accuracy. Along with a simple migration process, the tool keeps data hierarchy and structure intact throughout mailbox migration to Office 365.
Conclusion
Now you know the complete manual stepwise process for bulk mailbox migration to Office 365. It is efficient, but its long stepwise procedure, along with its limitations, makes it a complex one. Don’t get hassled with manual procedures; try out the trial with the automated Office 365 migration solution now!
