Migration to Zoho Mail
Zoho Mail offers a hassle-free data migration process for organizations who have their email hosted with other cloud-based service providers or on-premise email infrastructure to Zoho Mail. Based on the organization's requirements, administrators can transfer their existing data to Zoho Mail using one of the available migration types.
Steps to complete before Migration
Before you commence migrating to Zoho Mail, you must plan your migration and complete certain steps, to facilitate a successful transition:
- Add your organization's domain(s) in Zoho Mail.
- Verify the domain(s) in Zoho Mail.
- Create all users and groups in Zoho Mail. Follow the steps given on the user addition help page.
- Run a sample migration for 3 or 4 users to test the migration.
To have a seamless migration process, plan your migration, understand and choose the correct migration type, and adhere to the migration best practices.
Planning the migration
Below are a few recommendations to plan your migration:
- Weekends are suitable to switch your email service (low incoming emails).
- Inform the users about the change of email and provide the login details for the users before the switch.
- Change the MX to Zoho Mail. (Friday night/ Saturday early morning).
- Email Routing can be configured to avoid any loss of data.
- Create a catch-all account (not applicable in case of Split Delivery) to monitor and find out if any email addresses (groups/ users) were missed when creating the users.
Types of Migration
Selecting the migration type that suits your organization's requirements is critical to ensure a smooth and proper migration. Zoho Mail supports the below migration types:
Read through the sections that follow, to determine which type works best under which situation.
One-click Migration
One-click migration is an authentication process in which administrators authorize Zoho to access their email, calendar and contacts data from their previous email provider. One-click migration, also known as App-based Migration, is currently supported only by Google Workspace and Microsoft 365. Open the desired link given in the Email provider specific migration section on this help page.
IMAP vs POP Migration
IMAP migration is a server-to-server migration process and the most recommended way to migrate emails to Zoho Mail. The user data from your source server will directly be migrated to the respective user accounts in Zoho Mail along with the email status and folder structure. This aids users to continue from where they left off. The user accounts need to be created in Zoho Mail before adding the migration.
Check whether your previous email provider supports IMAP migration. If IMAP is not supported, then you can migrate your emails via POP migration.
Advantages of IMAP Migration over POP
Zoho Mail supports both IMAP and POP Migration, but IMAP Migration has more advantages compared to POP Migration. Refer to the below table to know more about which migration would be ideal for your accounts:
| IMAP Migration | POP Migration |
| Migration of email along with folder details. | POP does not migrate along with folders. All emails are migrated to Inbox. |
| Email (Read/ Unread) Status is maintained. | All emails are retrieved as 'Unread' when migration via POP. |
Multiple Client support:
| Only Single Client support:
|
| The migration via IMAP is generally faster than normal. The migration report has detailed statistics. | The migration via POP is slower than IMAP Migration. |
| Specific failures in migration can be tracked accurately. The errors can be corrected and the migration can be rerun. | The failures in migration in POP cannot be tracked accurately from the retrieving server (Zoho Mail in this case). Hence the failure information will be vague. |
Zoho Exchange Migration Wizard
If your previous email service was run by an in-house/ on-premise Exchange Server (without POP/IMAP support) or the user's emails are available as offline PSTor EML files, then administrators can use Zoho's Exchange Migration Wizard to migrate the emails from Exchange Server to the respective user accounts in Zoho Mail. This wizard can also be used to discover users from Active Directory to their Zoho Mail organization accounts. You can download the Exchange migration tool from here.
Options available for migration using the Zoho Exchange Migration wizard are given in the below table:
| Migration | Description |
| PST Migration | |
| EML Migration | |
| Exchange Migration | |
| Active Directory Sync |
Things to Crosscheck
The exact folder and mail count can be rechecked from the ‘View Folder Details’ option on the ‘Archive Policy’ page. This page will list the folder-wise email count and the mailbox size.
Migration Best Practices
- Run a sample migration for around 2 to 10 users before the actual email migration process. This will help us know the source server behaviour (user limit, mail size limit, speed of migration etc.)
- The maximum connection limit is the number of connections accepted by a server at a given time. Set the maximum number of connections depending upon the server load and the number of users.
- While setting up migration for a batch of users, set the priority for each user. Users whose priority is as ‘1’ will be migrated first, and the rest will follow according to the priority that you have set.
- Some servers will throttle the data fetch in IMAP after a certain interval. After that, the mail fetching for migration will be slow to avoid real-time mail traffic.
- The sample user's mailboxes should be migrated again to fetch the emails that got delivered before changing the MX. Duplication will be handled at our end. Alternatively, you can also set a date limit while adding the final migration for the sample users’ mailboxes to ensure that all emails after the sample migration have been migrated.
In general, to complete the migration for a batch of 25 users, each with a mailbox size of around 2 GB, and the maximum Connection Limit set to 10, it takes around 11 hours.