Migrate an IMAP / cPanel Mailbox to Microsoft 365

Is your email still living on shared hosting — cPanel, Roundcube, a webmail bundled with your domain name? Moving to Microsoft 365 gives you a more reliable mailbox, real anti-spam and the Outlook/Teams ecosystem. Rest assured: you can transfer every folder and your entire history into Exchange Online without losing a message, keeping delivery running throughout the cutover.

What gets migrated from IMAP hosting

A classic IMAP server (cPanel, Plesk, shared hosting, Roundcube webmail) stores emails and their folder tree. That structure is what we recover in full:

• Emails: inbox, folders, sub-folders, sent items and trash, with dates and attachments preserved.
• Folder tree: the hierarchy is recreated exactly in Exchange Online.

Watch a key point: with IMAP, contacts and calendars are usually not stored server-side — they often live in the webmail or locally. So they must be exported separately (CSV files for contacts, ICS for the calendar) and then imported into Microsoft 365. More on that below.

Step 1 · Audit before you migrate

First gather the essential technical details:

• the IMAP server (often mail.yourdomain.com), its port (993 over SSL) and the list of credentials for each mailbox;
• the size of each mailbox and the total number of accounts;
• the domain, its registrar and the current DNS/MX records — lower the TTL to 300 seconds a few days before cutover;
• any forwarders, aliases and shared mailboxes configured in cPanel.

On cPanel, you often need to know or reset the password of each mailbox, because IMAP migration connects to each one with its credentials.

Step 2 · Provision Microsoft 365

Create the users in the Microsoft 365 admin center with the same addresses as in IMAP, assign licenses, then add and verify the domain (TXT record at the registrar). Don't change the MX yet: mail keeps arriving on the original host until the copy is complete.

Step 3 · Migrate email with IMAP migration

Microsoft provides the native tool: IMAP migration, available in the Exchange admin center (Migration > Migrate to Exchange Online > IMAP migration). You supply a CSV file listing, for each mailbox, the destination address, the IMAP username and the password. The tool then opens a migration batch that copies messages in the background, folder by folder.

IMAP migration transfers mail only: that's perfect for shared hosting, but it's why contacts and calendars must be handled separately. The batch can be re-run incrementally to catch messages that arrived since the first pass, without creating duplicates.

Step 4 · Contacts, calendar and files

• Contacts: export them from the webmail (Roundcube exports to vCard/CSV) then import the file into Outlook / Microsoft 365.
• Calendar: export to ICS and import it into the Outlook calendar.
• Files: IMAP hosting includes no comparable cloud storage — use the migration to move useful documents into OneDrive or SharePoint via the OneDrive client.

As long as the MX records still point to the old server, no email is lost: the copy happens gently, and the final cutover lasts only as long as DNS propagation.

Step 5 · Switch DNS/MX without downtime

Once the initial copy is done, point the MX records to Microsoft 365 (format yourdomain-com.mail.protection.outlook.com). Add Microsoft's SPF, enable DKIM and publish a DMARC policy. Thanks to the lowered TTL, propagation takes a few dozen minutes; keep the old host active for a day or two to catch the last in-transit messages, then run a final delta.

Step 6 · Verify and configure Outlook

Confirm a test email lands in the new mailbox, then configure Outlook: most of the time, Microsoft 365 Autodiscover detects the settings automatically. On mobile, remove the old IMAP account and add an Exchange account or the Outlook app. Finally check signatures, filters and that all folders are present.

Common pitfalls

• Rate limits: shared hosting often caps simultaneous IMAP connections; an over-aggressive migration is throttled — spread it out.
• Duplicates: re-running a full batch instead of an incremental one duplicates messages.
• Special folders: Sent/Trash folders are sometimes named differently by the webmail and must be mapped correctly.
• Passwords: without up-to-date IMAP credentials, a mailbox can't be copied — plan a reset.
• Forgotten contacts and calendar: don't rely on IMAP migration to move them, export them manually.

How much it costs: Yuna7 vs an IT contractor

Having a contractor migrate an IMAP / cPanel mailbox to Microsoft 365 often costs several hundred dollars, with quotes and lead times. Yuna7 automates the cutover and you only pay for what you actually use — you can even try it for free.

Let Yuna7 migrate IMAP / cPanel to Microsoft 365 for you

Describe your migration in one sentence: Yuna7 audits your IMAP mailboxes and domain, provisions Microsoft 365, prepares the CSV file and launches the IMAP migration, imports contacts and calendar, drops your files into OneDrive, switches DNS/MX at the right moment and verifies everything arrived — you simply approve the sensitive steps. Far cheaper than a technician, and launched in minutes.