Move mailboxes from another provider to Plesk with IMAP import

Moving email is the most sensitive part of switching hosting: users expect all their old messages and no lost mail during the change. With IMAP you can copy every folder from the old provider to Plesk before switching DNS, then run a final sync afterwards.

Before you start

• Login details (address and password, or an app password) for each old mailbox, with IMAP enabled at the old provider.
• The domain added in Plesk; for whole websites from cPanel, the Plesk Migrator moves mail automatically, so this guide is for other sources.
• Lower the TTL of the domain's MX record to 300 seconds a day before the switch.

Create the mailboxes in Plesk

Create every mailbox with the same address and a temporary or the same password; see create email accounts in Plesk. Set quotas large enough for the old mail.

Option A: Plesk Email Importing extension

1. Administrators: install Email Importing (Plesk Email Migrator) from Extensions → Extensions Catalog.
2. Open the mailbox in Plesk and choose Import Mail (or open the extension).
3. Enter the old IMAP server (for example imap.gmail.com, port 993, SSL), the old login and password.
4. Start the import. Plesk copies folders and messages in the background and reports when done.

Option B: imapsync over SSH

For many mailboxes, imapsync run from any Linux server is reliable and repeatable:

imapsync --host1 imap.oldhost.com --user1 info@example.com --password1 'OLD' --host2 mail.example.com --user2 info@example.com --password2 'NEW' --ssl1 --ssl2

Put the command in a loop over a CSV of mailboxes for bulk moves. Re-running only copies new messages.

Switch MX records

1. After the first full copy, change the domain's MX record to the Plesk server (or switch nameservers if Plesk hosts DNS). See DNS records in Plesk.
2. Update SPF to include the new server and enable DKIM in Plesk.
3. Wait until the old TTL has passed.

Final sync and user setup

• Run the import or imapsync again to catch messages that arrived at the old provider during propagation.
• Give users the new settings – email client settings – or let autodiscover handle it.
• Keep the old mailboxes for a week before cancelling them.

Special cases

• Gmail / Google Workspace: enable IMAP and use an app password with 2-step verification. Gmail labels become folders.
• Microsoft 365: basic IMAP auth may be disabled; use the provider's export (PST) and import with an email client, or an OAuth-capable migration tool.
• POP3-only users: their mail lives on their computer; nothing to migrate server-side.

Troubleshooting

• Authentication failed on the old server: IMAP disabled or an app password required.
• Import stops at quota: raise the mailbox quota in Plesk.
• Duplicates after re-running: imapsync avoids duplicates by default; mixing tools can create them.

Next steps

• SPF, DKIM and DMARC.
• Spam filtering.
• Forwarders and auto-replies.