Migration to Zoho Mail

Migration to Zoho Mail

Email migration from current email servers to Zoho Mail servers:

Zoho Mail offers a very simple solution to migrate data from your previous email provider to the respective user account in Zoho Mail directly. 

Migration from G Suite:

If your email was previously hosted with G Suite, you can migrate to Zoho Mail using the migration options that are specific to G Suite.

G Suite migration has multiple advantages over Gmail IMAP migration since you can also migrate your Calendar and Contacts data along with email. Further migration to G Suite can be done by using just the Administrator credentials. Refer here for detailed instructions on G Suite migration.

Migration from Office 365:

If your email service was hosted with Office 365 previously, the administrator can make use of the Office 365 migration option in the Zoho Mail Control Panel. This will migrate not just the emails, but also the calendar and contact details saved under each user's account. 

Follow this help page for more details on specific migration from Office 365.

IMAP / POP Migration:

The most recommended way to migrate emails to Zoho Mail if your email was previously was not hosted with either G Suite or Office 365 is IMAP Migration. After migration, they can continue from where they left, as the email statuses and email folders are maintained and migrated in IMAP Migration. 

In case your previous email server does not support IMAP, then the emails can also be migrated via POP migration. Refer here for detailed instructions.

Zoho Exchange / Outlook 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 the administrator can use 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.

Best Practices

  1. Run a sample migration for around 2 to 10 users before the actual migration process. This will help us know the source server behavior (user limit, mail size limit, speed of migration etc.)
  2. 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.
  3. 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.
  4. 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 the real-time mail traffic.
  5. The sample users mailboxes should be migrated again to fetch the emails that got delivered before changing the MX. Duplication will be handled at our end. Alternately, 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 a 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 approximately takes 11 hours.

Choosing the right type of migration:

Choosing the migration type that suits the requirements of your organization is vital to ensure a smooth and proper migration. Each migration type is best suited for a specific type of users. Read through the next section to determine which type works best under which situation.

Advantages of IMAP Migration over POP:

If your emails are in a cloud-hosted email service like Google Apps or Yahoo or any other cloud email server which support IMAP Access, you can perform a server to server migration via IMAP from the Control Panel. 

Zoho Mail supports both IMAP and POP Migration, but IMAP Migration has more advantages compared to the POP Migration.

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:

  • Emails are migrated even if accessed by other clients.
  • The emails are synced in multiple clients with state maintenance
  • The emails available in the source mailbox is synced along with folder and state information.
  • The emails sent by other clients are synced via IMAP.

Only Single Client support:

  • If there are multiple client requests, the email is provided only to a single client.
  • The emails retrieved via POP already are not available for migration.
  • The emails sent by other clients will not be migrated, as it is not supported by POP Servers
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

PST Migration:

When to Use:

  • Migration might be performed by user or Admin
  • The user data is available as PST files.
  • All Mailbox data (Mail/Contacts/Calendar/Tasks/Notes) needs to be migrated to Zoho Mail.

Things to Crosscheck:

The exact folder and mail count can be rechecked from the ‘View Folder Details’ option in the ‘Archive Policy’ page. This page will list the folder-wise email count and the mailbox size.

EML Migration:

When to Use:

  • Migration might be performed by user or Admin
  • The only data to be migrated is the user's emails
  • User's email data is available as ZIP files, containing EML files.

Things to Crosscheck:

The exact folder and mail count can be rechecked from the ‘View Folder Details’ option in the ‘Archive Policy’ page. This page will list the folder-wise email count and the mailbox size.

Exchange Migration:

When to Use:

  • Admin can use the GAL or LDAP option to fetch user list for migration.
  • User data is available on an Exchange server.
  • All Mailbox data (Mail/Contacts/Calendar/Tasks/Notes) needs to be migrated to Zoho Mail.

Things to Crosscheck:

The exact folder and mail count can be rechecked from the ‘View Folder Details’ option in the ‘Archive Policy’ page. This page will list the folder-wise email count and the mailbox size.

Before Migration

1. Add domain(s) in Zoho Mail.

2. Verify domain(s) in Zoho Mail.

3. Create all users and groups in Zoho Mail.

4. Run sample migration for 3 or 4 users to test the migration.

5. Ideally, a weekend is suitable to switch the service (low incoming emails).

6. Inform the users about the switch of email and provide the login details for the users before the switch.

7. Change the MX to Zoho Mail. (Friday night/ Saturday early morning).

8. Email Routing can be configured to avoid any loss of data.

9. 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.

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