Transfer a Outlook / Microsoft 365 mailbox to Gmail
Copy your entire Outlook / Microsoft 365 mailbox to Gmail, folders and attachments included — no account needed, with the right IMAP settings already set up.
IMAP server and port already filled in for Outlook / Microsoft 365 and Gmail — all that's left is to enter your credentials.
IMAP settings for Outlook / Microsoft 365 and Gmail
Source mailbox — Outlook / Microsoft 365
- IMAP server
- outlook.office365.com
- Port
- 993
- Encryption
- SSL/TLS
- App password
- Required
Destination mailbox — Gmail
- IMAP server
- imap.gmail.com
- Port
- 993
- Encryption
- SSL/TLS
- App password
- Required
Microsoft has disabled basic IMAP authentication on most personal and work accounts: an app password (or reconnecting via modern authentication) is required as soon as two-factor authentication is enabled.
Gmail requires an app password: your regular password is rejected over IMAP once 2-step verification is on. Without 2-step verification, Google blocks "less secure app" IMAP connections anyway, so an app password remains the most reliable option.
App password for Outlook / Microsoft 365: Generate an app password from your Microsoft account security settings if two-factor authentication is on.
App password for Gmail: Turn on 2-Step Verification, then generate an app password from your Google account's security settings.
How it works
- Enter the credentials for your Outlook / Microsoft 365 mailbox — the server (outlook.office365.com, port 993) is already filled in, all that's missing is your address and your app password.
- Enter the credentials for your Gmail mailbox — same on the destination side (imap.gmail.com, port 993).
- Start the transfer — MailSync connects to both mailboxes and copies the messages folder by folder.
- Follow the progress in real time — you can close the page, the operation keeps running in the background.
- Check the result — find all your messages and folders in your Gmail mailbox.
What this tool doesn't do
- The operation only works over IMAP: a mailbox reachable only via POP3, or through a closed proprietary connector, can't be used.
- Server-side filtering rules, signatures or auto-replies are not copied: only the messages and their folder organization are.
- Beyond 5GB, finishing the operation requires a one-off payment or the Premium plan.
Frequently asked questions
Do I need an app password for Outlook / Microsoft 365? +
Yes. Generate an app password from your Microsoft account security settings if two-factor authentication is on. Microsoft has disabled basic IMAP authentication on most personal and work accounts: an app password (or reconnecting via modern authentication) is required as soon as two-factor authentication is enabled.
Do I need an app password for Gmail? +
Yes. Turn on 2-Step Verification, then generate an app password from your Google account's security settings. Gmail requires an app password: your regular password is rejected over IMAP once 2-step verification is on. Without 2-step verification, Google blocks "less secure app" IMAP connections anyway, so an app password remains the most reliable option.
Are messages deleted from my Outlook / Microsoft 365 mailbox? +
No, never automatically. MailSync copies your messages from Outlook / Microsoft 365 to Gmail, it doesn't move them: your Outlook / Microsoft 365 mailbox stays intact after the operation. You can empty it yourself once you've checked the copy, if you want to.
How long does a transfer from Outlook / Microsoft 365 to Gmail take? +
It mostly depends on the volume of your Outlook / Microsoft 365 mailbox and the write speed accepted by the Gmail server. Usually a few minutes for a few hundred messages, longer for a large volume. You can follow progress in real time and close the page.
Is there a volume limit for this transfer? +
The transfer from Outlook / Microsoft 365 to Gmail is free up to 5GB. Beyond that, the first 5GB are transferred for free; then finish the operation for 4,99€ excl. VAT (5,99€ incl. VAT) or switch to Premium.
Are my Outlook / Microsoft 365 credentials stored? +
No. Your IMAP credentials are encrypted with libsodium for the duration of the operation, then erased as soon as it finishes. If you're signed in to your MailSync account and choose to save the mailbox, only that one is kept (encrypted); you can delete it at any time.