Zimbra to Office 365 Migration: How-to Guide

To migrate Zimbra to Office 365:

1. Prepare for your migration.

Start by determining the scope of your migration. Consider whether you need to transfer only emails or include contacts, calendars, or other data critical to your workflow as well.

Next, establish a timeline. The migration's duration depends on the number of mailboxes and the amount of data to be transferred. Evaluate your deadlines and plan backward to allocate sufficient time for preparation, migration, and verification. Remember that larger migrations may take several days, so consider adding a few more days to your timeline just to be safe.

2. Create a backup of your content.

Before starting migrating your content, it's always a good idea to create a backup of your most important Zimbra emails. Third-party automated tools for email migrations provide accurate results and do not usually require a backup. However, free migration methods are riskier, so having a backup will allow you to recover the data if anything goes wrong.

For example, you can export your email data into a file format like .pst and store it securely.

3. Choose a migration method.

There are two approaches to migrating emails:

• Using paid third-party tools for a fully automated experience
• Using free tools that require a lot of manual setup

The choice depends on multiple factors, including the scope of your migration and the availability of resources (time, money, and technical skills).

Microsoft's native migration tools, while free, require a lot of manual work and expertise, while third-party tools like VaultMe automate most tasks. For more information on what you should consider when choosing a migration method, see this article: How to Choose an Email Migration Tool.

4. Sign up for Office 365.

Buy an Office 365 subscription and create accounts for all users, if necessary. If you have your domain, you can continue using it with your Microsoft 365 Office subscription: simply sign up for Office 365 with your primary (admin) email address and verify the ownership of the domain during the sign-up process. However, you can also change your domain and create brand-new email addresses in Office 365.

Then, activate OneDrive for each user in the organization. You must do that prior to the migration. To activate OneDrive, users must sign in to their OneDrive accounts at least once. Alternatively, you can activate user OneDrive accounts on your own using the following instructions: Pre-provision OneDrive for users in your organization.

5. Transfer your mailbox(es).

Once you've chosen a migration method, it's time to transfer your mailboxes. But before you begin, ensure that each user account has sufficient storage space in Office 365. By default, users may have 50 or 100 GB of mailbox space in Outlook Office 365.

Then, follow the instructions for your selected approach and monitor your migration. Paid automated tools often provide real-time updates, while free approaches often require manually ensuring the process goes as planned.

6. Verify the results.

After the migration process is complete, it’s important to verify that all data has been transferred successfully. This can include ensuring that:

• The folder structure from Zimbra has been preserved in Office 365 (where applicable).
• All emails, including older messages and archived folders, have been transferred accurately.
• Attachments are intact and accessible in their respective emails.

Additionally, review your migration report, if available. While VaultMe generates detailed migration reports for each account, other tools, including free Microsoft ones, do not usually have reports.

7. Change MX records.

If you've chosen to keep your email addresses, once you’ve reviewed the migration results and are ready to fully transition to Office 365, update your domain’s MX records to direct incoming emails to Office 365. MX records are DNS records that indicate how the incoming email should be routed. All future emails will start arriving in Office 365 instead of Zimbra only after you update the MX records.

MX records can be changed through your domain registrar or hosting provider. Microsoft provides detailed instructions on setting these records in this article: Add DNS records to connect your domain.

8. Close your Zimbra account.

If you no longer intend to use your Zimbra account, consider closing it to avoid unnecessary costs or maintenance. Deleting unused accounts is a recommended best practice to reduce the risk of identity theft and maintain security.

We recommend waiting at least 30 days after the migration before deleting the old account.

To migrate Zimbra emails to Office 365 automatically:

1. Navigate to the VaultMe app.

2. Select "Migrate or archive multiple user accounts (advanced)." If you have only one or two user accounts, you can use VaultMe for Individuals and migrate your accounts one by one. In this case, select "Migrate a single user account to another account."

   

3. Create your VaultMe for Admins profile.

4. Select your source and destination service providers. For the source service provider, choose "IMAP." For the destination service provider, choose "Microsoft 365."

5. Decide how you want to connect your source accounts. Since domain authorization is unavailable for IMAP migrations, you can connect each source account on your own or send sign-in links to users and instruct them to connect their accounts.

6. Connect your destination accounts. We recommend using domain authorization for your Office 365 / Microsoft 365 accounts.

7. Add user accounts to the migration plan.

8. Review the information regarding the data VaultMe will be able to migrate.

9. Decide if you want to merge the copied emails with those in the destination accounts or put them into separate folders.

10. Review the price breakdown and proceed to checkout. VaultMe's prices are outlined on this page: VaultMe's Pricing. Refer to the VaultMe for Admins pricing.

11. Begin your migration. You can safely close your browser or power off your computer without interrupting the process.

12. Track the progress of your Zimbra to Office 365 migration using the real-time updates on your migration page (optional). You’ll receive an email notification when your migration is complete.

13. Check the results and download your migration report. Additionally, you can download your invoice from the migration page.

To manually migrate a Zimbra Mail Mailbox to Office 365:

1. Install the Outlook app on your computer.

2. Connect your Zimbra and Office 365 Outlook accounts to the app.

3. In the left-hand menu, navigate to your Zimbra account. In the top menu, go to File > Export.

4. Select "Emails," then click "Continue." Download the suggested .olm file (on a Mac computer) or the .pst file (on a Windows machine).

   

5. In the left-hand menu, go to your Office 365 account. In the top menu, navigate to File > Import.

6. Select the file that you downloaded.

   

7. Allow time for the emails to upload to your Office 365 account. This process can take several hours or even days, depending on the size of your account. Keep your computer powered on and ensure your internet connection remains stable throughout.

8. Check the results.