Migrate from Gmail to mailcow

Export

1. 1

   Step 1

   Turn IMAP on

   In Gmail settings, enable IMAP for the mailbox you are leaving. mailcow's docs use imapsync against a remote IMAP server, so the mailbox has to accept that login.

2. 2

   Step 2

   Take a Takeout copy

   Google Takeout can export the mailbox as a second copy. Keep it until you have read the new inbox and checked a few old threads. Do not delete the Google account on day one.

3. 3

   Step 3

   Write down filters and aliases

   Filters, send-as addresses, and forwarding rules are not part of the IMAP copy. Screenshot or export the list before you change DNS.

Import

1. 1

   Step 1

   Stand up mailcow first

   Install mailcow: dockerized and create the domain and mailboxes. SOGo is the browser inbox. Confirm you can send and receive on a test address before you touch the real domain.

2. 2

   Step 2

   Run imapsync

   mailcow documents imapsync for pulling a remote mailbox. Point it at the Gmail account and the new mailbox. Run it once as a rehearsal, then again just before you cut DNS.

3. 3

   Step 3

   Move MX last

   Change the domain's mail records only after the rehearsal import looks right. New mail starts arriving on mailcow. The old Gmail copy stops growing.

What breaks

• Labels and categories

  Gmail labels and the Primary/Social tabs do not become mailcow folders. Expect IMAP folders and a Junk folder, not the Gmail sidebar.

• Drive, Calendar, Meet

  Those are not part of this move. SOGo has calendars and contacts. Google Drive files stay in Google until you move them separately.

• Deliverability

  A new server has no reputation. Set the DNS records mailcow documents, and expect some mail to land in other people's spam until that settles.