Imapsync is an IMAP Transfer Tool used for Transferring Mailboxes and Emails from one IMAP Server to Another IMAP server. Imapsync Application is a command-line Tool that allows Incremental and Recursive IMAP Transfers from One Mailbox to Another, both anywhere on the Internet or in your Local Area Network.

Transfer Mailboxes with Imapsync

So you are ready for migration. Before migration make sure both accounts have IMAP running and accessible from your system. After that use following command syntax.

sudo imapsync --host1 imap.source.example.com --user1 user@example.com --password1 'S0urcePassw0rd' --ssl1 --host2 imap.dest.example.com --user2 user@example.com --password2 'Dest1nat10NPassw0rd' --ssl2

The above Command might take a long time as per the Size of your Source Mailbox. After Completing All Process, you will see a long list of output. Check the Output to find if any error occurred during transfer. Below is a small part of the Result.

Transfer started at Thu June 11 11:45:00 2019
PID is 4969
...
...
...
Total bytes transferred           : 78373 (76.536 KiB)
Total bytes duplicate host1       : 0 (0.000 KiB)
Total bytes duplicate host2       : 0 (0.000 KiB)
Total bytes skipped               : 0 (0.000 KiB)
Total bytes error                 : 0 (0.000 KiB)
Message rate                      : 0.1 messages/s
Average bandwidth rate            : 3.0 KiB/s
Memory consumption                : 217.0 MiB
Biggest message                   : 57947 bytes (56.589 KiB)
Memory/biggest message ratio      : 3927.0
Start difference host2 - host1    : -2 messages, -78373 bytes (-76.536 KiB)
Final difference host2 - host1    : 0 messages, 0 bytes (0.000 KiB)
Detected 0 errors