IMAP synchronisation, sync, copy or migration tool. Synchronise mailboxes between two imap servers. Good at IMAP migration. More than 44 different IMAP server softwares supported with success. $Revision: 1.525 $


Synchronize IMAP account between host1 and host2

$ imapsync --host1 [host1] --user1 [user1] --password1 [secret1] --host2 [host2] --user2 [user2] --password2 [secret2]


imapsync - IMAP synchronisation, sync, copy or migration tool. Synchronise mailboxes between two imap servers. Good at IMAP migration. More than 44 different IMAP server softwares supported with success.

$Revision: 1.525 $


To synchronize imap account "foo" on "" to imap account "bar" on "" with foo password "secret1" and bar password "secret2":

imapsync \ --host1 --user1 foo --password1 secret1 \ --host2 --user2 bar --password2 secret2


imapsync works fine under any Unix OS with perl. imapsync works fine under Windows (2000, XP) with Strawberry Perl 5.10 or 5.12 or as a standalone binary software imapsync.exe
imapsync can be available directly on the following distributions: FreeBSD, Debian, Ubuntu, Gentoo, Fedora, NetBSD, Darwin, Mandriva and OpenBSD.
Purchase latest imapsync at You'll receive a link to a compressed tarball called imapsync-x.xx.tgz where x.xx is the version number. Untar the tarball where you want (on Unix): tar xzvf imapsync-x.xx.tgz Go into the directory imapsync-x.xx and read the INSTALL file. The INSTALL file is also at The freecode (was freshmeat) record is at


imapsync [options]
To get a description of each option just run imapsync like this:
imapsync --help imapsync
The option list:
imapsync [--host1 server1] [--port1 <num>] [--user1 <string>] [--passfile1 <string>] [--host2 server2] [--port2 <num>] [--user2 <string>] [--passfile2 <string>] [--ssl1] [--ssl2] [--tls1] [--tls2] [--authmech1 <string>] [--authmech2 <string>] [--proxyauth1] [--proxyauth2] [--domain1] [--domain2] [--authmd51] [--authmd52] [--folder <string> --folder <string> ...] [--folderrec <string> --folderrec <string> ...] [--include <regex>] [--exclude <regex>] [--prefix2 <string>] [--prefix1 <string>] [--regextrans2 <regex> --regextrans2 <regex> ...] [--sep1 <char>] [--sep2 <char>] [--justfolders] [--justfoldersizes] [--justconnect] [--justbanner] [--syncinternaldates] [--idatefromheader] [--syncacls] [--regexmess <regex>] [--regexmess <regex>] [--maxsize <int>] [--minsize <int>] [--maxage <int>] [--minage <int>] [--skipheader <regex>] [--useheader <string>] [--useheader <string>] [--nouid1] [--nouid2] [--usecache] [--skipsize] [--allowsizemismatch] [--delete] [--delete2] [--expunge] [--expunge1] [--expunge2] [--uidexpunge2] [--delete2folders] [--delete2foldersonly] [--delete2foldersbutnot] [--subscribed] [--subscribe] [--subscribe_all] [--nofoldersizes] [--nofoldersizesatend] [--dry] [--debug] [--debugimap][--debugimap1][--debugimap2] [--timeout <int>] [--fast] [--split1] [--split2] [--reconnectretry1 <int>] [--reconnectretry2 <int>] [--noreleasecheck] [--pidfile <filepath>] [--tmpdir <dirpath>] [--version] [--help] [--tests] [--tests_debug]


The command imapsync is a tool allowing incremental and recursive imap transfer from one mailbox to another.

By default all folders are transferred, recursively.

We sometimes need to transfer mailboxes from one imap server to another. This is called migration.

imapsync is a good tool because it reduces the amount of data transferred by not transferring a given message if it is already on both sides. Same headers and the transfer is done only once. All flags are preserved, unread will stay unread, read will stay read, deleted will stay deleted. You can stop the transfer at any time and restart it later, imapsync works well with bad connections.

You can decide to delete the messages from the source mailbox after a successful transfer, it can be a good feature when migrating live mailboxes since messages will be only one side. In that case, use the --delete option. Option --delete implies also option --expunge so all messages marked deleted on host1 will be really deleted. (you can use --noexpunge to avoid this but I don't see any good real world scenario for the combinaison --delete --noexpunge).

You can also just synchronize a mailbox B from another mailbox A in case you just want to keep a "live" copy of A in B. In that case --delete2 can be used, it deletes messages in host2 folder B that are not in host1 folder A.

imapsync is not adequate for maintaining two active imap accounts in synchronization where the user plays independently on both sides. Use offlineimap (written by John Goerzen) or mbsync (written by Michael R. Elkins) for 2 ways synchronizations.


To get a description of each option just invoke:

imapsync --help


I wrote imapsync because an enterprise (basystemes) paid me to install a new imap server without losing huge old mailboxes located on a far away remote imap server accessible by a low bandwidth link. The tool imapcp (written in python) could not help me because I had to verify every mailbox was well transferred and delete it after a good transfer. imapsync started life as a patch. The tool comes from the Mail-IMAPClient-2.1.3 perl module tarball source (in the examples/ directory of the tarball).


While working on imapsync parameters please run imapsync in dry mode (no modification induced) with the --dry option. Nothing bad can be done this way.

To synchronize the imap account "buddy" (with password "secret1") on host "" to the imap account "max" (with password "secret2") on host "":

imapsync --host1 --user1 buddy --password1 secret1 \ --host2 --user2 max --password2 secret2
Then you will have max's mailbox updated from buddy's mailbox.


You can use --passfile1 instead of --password1 to give the password since it is safer. With --password1 option any user on your host can see the password by using the 'ps auxwwww' command. Using a variable (like $PASSWORD1) is also dangerous because of the 'ps auxwwwwe' command. So, saving the password in a well protected file (600 or rw-------) is the best solution.

imasync is not totally protected against sniffers on the network since passwords may be transferred in plain text if CRAM-MD5 is not supported by your imap servers. Use --ssl1 (or --tls1) and --ssl2 (or --tls2) to enable encryption on host1 and host2.

You may authenticate as one user (typically an admin user), but be authorized as someone else, which means you don't need to know every user's personal password. Specify --authuser1 "adminuser" to enable this on host1. In this case, --authmech1 PLAIN will be used by default since it is the only way to go for now. So don't use --authmech1 SOMETHING with --authuser1 "adminuser", it will not work. Same behavior with the --authuser2 option.

When working on Sun/iPlanet/Netscape IMAP servers you must use --proxyauth1 to enable administrative user to masquerade as another user. Can also be used on destination server with --proxyauth2

Exit Status

imapsync will exit with a 0 status (return code) if everything went good. Otherwise, it exits with a non-zero status.

So if you have an unreliable internet connection, you can use this loop in a Bourne shell:

while ! imapsync ...; do echo imapsync not complete done


imapsync is free, open, public but not always gratis software cover by the NOLIMIT Public License. See the LICENSE file included in the distribution or just read this: No limit to do anything with this work and this license.


The public mailing-list may be the best way to get support.

To write on the mailing-list, the address is: <>

To subscribe, send any message (even empty) to: <> then just reply to the confirmation message.

To unsubscribe, send a message to: <>

To contact the person in charge for the list: <>

The list archives may be available at: So consider that the list is public, anyone can see your post. Use a pseudonym or do not post to this list if you want to stay private.

Thank you for your participation.


Gilles LAMIRAL <>

Feedback good or bad is always welcome.

The newsgroup comp.mail.imap may be a good place to talk about imapsync. I read it when imapsync is concerned. A better place is the public imapsync mailing-list (see below).

Gilles LAMIRAL earns his living writing, installing, configuring and teaching free, open and often gratis softwares. Do not hesitate to pay him for that services.

Bug Report Guidelines

Help us to help you: follow the following guidelines.

Report any bugs or feature requests to the public mailing-list or to the author.

Before reporting bugs, read the FAQ , the README and the TODO files.

Upgrade to last imapsync release, maybe the bug is already fixed.

Upgrade to last Mail-IMAPClient Perl module. maybe the bug is already fixed.

Make a good title with word "imapsync" in it (my spam filter won't filter it), Don't write an email title with just "imapsync" or "problem", a good title is made of keywords summary, not too long (one visible line).

Don't write imapsync in uppercase in the email title, we'll know you run Windows and you haven't read this README yet.

Help us to help you: in your report, please include:

- imapsync version. - output given with --debug --debugimap near the failure point. Isolate a message or two in a folder 'BUG' and use imapsync ... --folder 'BUG' --debug --debugimap - imap server software on both side and their version number. - imapsync with all the options you use, the full command line you use (except the passwords of course). - version. - the run context. Do you run imapsync.exe, a unix binary or the perl script imapsync. - operating system running imapsync. - virtual software context (vmware, xen etc.) - operating systems on both sides and the third side in case you run imapsync on a foreign host from the both.
Most of those values can be found as a copy/paste at the begining of the output.

One time in your life, read the paper "How To Ask Questions The Smart Way" and then forget it.

Imap Servers

Failure stories reported with the following 3 imap servers:

- MailEnable 1.54 (Proprietary) but MailEnable 4.23 is supported. - DBMail 0.9, 2.0.7 (GPL). But DBMail 1.2.1 is supported. Patient and confident testers are welcome. - Imail 7.04 (maybe). - (2011) MDaemon 12.0.3 as host2 but MDaemon is supported as host1. MDaemon is simply buggy with the APPEND IMAP command with any IMAP email client.
Success stories reported with the following 48 imap servers (software names are in alphabetic order):
- 1und1 H mimap1 84498 [host1] - IMAP4 Ready [host1] - Archiveopteryx 2.03, 2.04, 2.09, 2.10 [host2], 3.0.0 [host2] (OSL 3.0) - Axigen Mail Server Version 8.0.0 - BincImap 1.2.3 (GPL) ( - CommuniGatePro server (Redhat 8.0) (Solaris), CommuniGate Pro 5.2.17[host2] (CentOS 5.4) - Courier IMAP 1.5.1, 2.2.0, 2.1.1, 2.2.1, 3.0.8, 3.0.3, 4.1.1 (GPL) ( - Critical Path (7.0.020) - Cyrus IMAP 1.5, 1.6, 2.1, 2.1.15, 2.1.16, 2.1.18 2.2.1, 2.2.2-BETA, 2.2.3, 2.2.6, 2.2.10, 2.2.12, 2.2.13, 2.3-alpha (OSI Approved), 2.3.1, 2.3.7, 2.3.16 ( - David Tobit V8 (proprietary Message system). - Deerfield VisNetic MailServer 5.8.6 [host1] ( - DBMail 1.2.1, 2.0.4, 2.0.9, 2.2rc1 (GPL) ( 2.0.7 seems buggy. - Deerfield VisNetic MailServer 5.8.6 [host1] - dkimap4 [host1] - Domino (Notes) 4.61[host1], 6.5[host1], 5.0.6, 5.0.7, 7.0.2, 6.0.2CF1, 7.0.1[host1], 8.0.1[host1], 8.5.2[host2] - Dovecot, 0.99.14, 0.99.14-8.fc4, 1.0-0.beta2.7, 1.0.0 [dest/source] (LGPL) ( - Eudora WorldMail v2 - Gimap (Gmail imap) - GMX IMAP4 StreamProxy. - Groupwise IMAP (Novell) 6.x and 7.0. Buggy so see the FAQ. - hMailServer 5.3.3 [host2], 4.4.1 [host1] (see FAQ) - iPlanet Messaging server 4.15, 5.1, 5.2 - IMail 7.15 (Ipswitch/Win2003), 8.12, 11.03 [host1] - Kerio 7.2.0 Patch 1 [host1] [host2] - MailEnable 4.23 [host1] [host2], 4.26 [host1][host2], 5 [host1] - MDaemon 7.0.1, 8.0.2, 8.1, 9.5.4 (Windows server 2003 R2 platform), 12 [host2], 12.0.3 [host1], 12.5.5 [host1], - Mercury 4.1 (Windows server 2000 platform) - Microsoft Exchange Server 5.5, 6.0.6249.0[host1], 6.0.6487.0[host1], 6.5.7638.1 [host2], 6.5 [host1], Exchange 2007 SP1 (with Update Rollup 2), Exchange2007-EP-SP2, Exchange 2010 RTM (Release to Manufacturing) [host2], Exchange 2010 SP1 RU2[host2], - Mirapoint, 4.1.9-GA [host1] - Netscape Mail Server 3.6 (Wintel !) - Netscape Messaging Server 4.15 Patch 7 - OpenMail IMAP server B.07.00.k0 (Samsung Contact ?) - OpenWave - Oracle Beehive [host1] - Qualcomm Worldmail (NT) - Rockliffe Mailsite 5.3.11, 4.5.6 - Samsung Contact IMAP server 8.5.0 - Scalix v10.1,,, 11.4.6 - SmarterMail, Smarter Mail 5.0 Enterprise, Smarter Mail 5.5 [host1], SmarterMail Professional 10.2 [host1]. - Softalk Workgroup Mail 7.6.4 [host1]. - SunONE Messaging server 5.2, 6.0 (SUN JES - Java Enterprise System) - Sun Java(tm) System Messaging Server 6.2-2.05, 6.2-7.05, 6.3 - Surgemail 3.6f5-5 - UW-imap servers (imap-2000b) rijkkramer IMAP4rev1 2000.287 (RedHat uses UW like 2003.338rh), v12.264 Solaris 5.7 (OSI Approved) ( - UW - QMail v2.1 - VMS, Imap part of TCP/IP suite of VMS 7.3.2 - Yahoo [host1] - Zimbra-IMAP 3.0.1 GA 160, 3.1.0 Build 279, 4.0.5, 4.5.2, 4.5.6, Zimbra 5.0.24_GA_3356.RHEL4 [host1], 5.5, 6.x
Please report to the author any success or bad story with imapsync and do not forget to mention the IMAP server software names and version on both sides. This will help future users. To help the author maintaining this section report the two lines at the begining of the output if they are useful to know the softwares. Example:
Host1 software:* OK louloutte Cyrus IMAP4 v1.5.19 server ready Host2 software:* OK Courier-IMAP ready
You can use option --justconnect to get those lines. Example:
imapsync --host1 --host2 --justconnect

Huge Migration

Pay special attention to options --subscribed --subscribe --delete --delete2 --delete2folders --maxage --minage --maxsize --useuid --usecache

If you have many mailboxes to migrate think about a little shell program. Write a file called file.txt (for example) containing users and passwords. The separator used in this example is ';'

The file.txt file contains:

user001_1;password001_1;user001_2;password001_2 user002_1;password002_1;user002_2;password002_2 user003_1;password003_1;user003_2;password003_2 user004_1;password004_1;user004_2;password004_2 user005_1;password005_1;user005_2;password005_2 ...

On Unix the shell program can be:

{ while IFS=';' read u1 p1 u2 p2; do imapsync --host1 --user1 "$u1" --password1 "$p1" \ --host2 --user2 "$u2" --password2 "$p2" ... done ; } < file.txt
On Windows the batch program can be:
FOR /F "tokens=1,2,3,4 delims=; eol=#" %%G IN (file.txt) DO imapsync ^ --host1 --user1 %%G --password1 %%H ^ --host2 --user2 %%I --password2 %%J ...
The ... have to be replaced by nothing or any imapsync option.

Welcome in shell programming !


Feel free to hack imapsync as the NOLIMIT license permits it.


Entries for imapsync:

Similar Softwares

imap_tools : offlineimap : mbsync : mailsync : mailutil : part of the UW IMAP tookit. imaprepl : imapcopy : migrationtool : imapmigrate : wonko_imapsync: see also file W/tools/wonko_ruby_imapsync exchange-away : pop2imap :
Feedback (good or bad) will often be welcome.

$Id: imapsync,v 1.525 2013/02/05 12:52:10 gilles Exp gilles $

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