Official imapsync migration tool ( release <!--#exec cmd="cat ./VERSION"--> )
Author: Gilles LAMIRAL
Description: Imapsync is an IMAP sync tool. It syncs all folders from one mailbox to another, both anywhere on the Internet or in your local network.
Keywords: imap, transfer, migration, backup

# Imapsync

# The Mailbox Changer

## Afraid of losing all your precious emails?
It's time to copy all of them elsewhere!
Safely.

Site last updated on
Why this website looks so old fashion?

## What is imapsync? (back to menu)

Imapsync presentation by Gilles

Imapsync is an IMAP transfer tool. The purpose of imapsync is to migrate IMAP accounts or to backup IMAP accounts. IMAP, IMAP4 in fact (started December 1994), is one of the three current standard protocols used to access mailboxes, the two other being POP3 (started November 1988) and HTTP (started May 1996) with webmails, webmails are often tied to an IMAP server.

The latest imapsync published release was written on

Imapsync 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 network. Imapsync runs on Windows, Linux, Mac OS X. "Incremental" means you can stop the transfer at any time and restart it later efficiently, without generating duplicates. "Recursive" means the complete folders hierarchy can be copied, all folders, all subfolders etc. "Command-line" means it's not a graphical tool, on Windows you have to run imapsync from a batch file. Anyway there is a visual online service, you can try imapsync online at https://imapsync.lamiral.info/X/

## What imapsync can't do? (back to menu)

Imapsync can't migrate Contacts and Calendars. Most email systems don't set or get Contacts or Calendars via the IMAP protocol. No way via IMAP, no way via imapsync but it can be done with other tools or via export/import of csv or ics files. Also consider using caldavsynchronizer or asking experts at Sumatra company.

Imapsync is not suitable for maintaining a synchronization between two active imap accounts while the user is working on both sides. See why in the Two Ways Sync document. Use offlineimap (written by John Goerzen) or mbsync (written by Michael R. Elkins) for bidirectional (2 ways) synchronizations.

Imapsync can't backup nor restore email messages to or from a local directory. Imapsync works only with IMAP accounts, which always belong to some IMAP server. Read the Archiving document to get several solutions, at least four solutions, to this issue.

Alternatives to imapsync are listed in the Similar softwares section.

Alternatives to the imapsync online service are listed in the External online services section.

## Imapsync Quiz

## Contact the author, Gilles LAMIRAL (back to menu)

Gilles LAMIRAL
gilles@lamiral.info
work cel: +33 6 19 22 03 54
work desk: +33 9 51 84 42 42
Postal address:
22 La Billais
BAULON 35580
FRANCE

Good feedback is always welcome!
and bad feedback is very often welcome

It may sounds crazy but I do reply personally to every single email message I receive, so don't hesitate to spend time writing to me about your email problems, you're sure to get my attention and my time.

## Buy imapsync and support (back to menu)

> Imapsync was the best investment I've ever done.

> — Uwe Keim Dec 6 '16 at 12:17

Read some other nice and true testimonials from users.

There is no trial version but I offer 30-day money back guarantee whatever the reason for a refund. Or drop me a gentle email and I will provide you the latest imapsync because, well, you made the effort to contact me.
After downloading imapsync, go to the installation documentation.

Special offer: it's only €120 EUR if you buy imapsync + support at once (instead of 60 + 120 = 180 EUR).

For €120 EUR you will get:

- Imapsync full professional support (that costs also €120 EUR by itself, see why below).
- Access without any limit to the imapsync online service, like /X.
- Standalone imapsync.exe for win32, easy installation done by a zip extraction anywhere. See README_Windows.txt for details.
- Standalone imapsync_bin_Darwin for Mac OS X. (Catalina ok with a permission deed)
- Imapsync Perl source code for any operating system, Unix, Windows, OS X.
- The visual interface, similar to /X, to install the service on your own Linux server (not working on Windows yet).
- Lifetime of imapsync updates without extra payment.
- 30-day money back guarantee! No question nor condition to get a refund, really, just request it and you'll sure get a refund!
- No limit to do anything with imapsync and its license.

For €60 EUR you will get all the above except imapsync full professional support (the first line).

For €120 EUR independently, you get imapsync full professional support, provided by the imapsync designer and developer, Gilles LAMIRAL, your servitor, who has been supporting imap migrations with imapsync for more than 20 years (I started in 2001). See a detailed support description below.

You may wonder why the support alone is the same price as imapsync+support? It's because when you buy both at once, I'm not sure I will have to spend some time directly with you, it's possible that everything goes smoothly for you, since this aim is my daily work. But when you buy the support alone, after buying the software, then I will surely spend time (any amount of hours) to help you. Does it seem fair enough?

Imapsync buying options, select your choice by clicking on it:

Professionals buyers outside France are VAT exempted. Individuals or French buyers are VAT taxed.

In case you're a European professional buyer, please enter your VAT number: It is for accounting and customs declaration.
It's ok if you don't have your VAT number right now, I'll email you later for it.
VAT is often 2 letters followed by several digits, for example mine is FR74429303332.
If you're a European and you don't have a VAT number then select "Software only. For individual use." (it's at the bottom of the buying options, above).

If you can't use Paypal nor a credit card then consider a Bank transfer (I'll give you my IBAN on demand) or even a Crypto payment(very rare indeed so there is a very special offer here).

Instantly at the end of the payment, Paypal will proposed you to go back to the site, via a link to gilles@lamiral.info (it's my paypal account name), this link brings you to imapsync download.
You will also receive an email from gilles@lamiral.info a few minutes later (it can fall in the Spam folder sometimes).
In order to get an accurate invoice, please make sure the delivery postal address you enter in Paypal suits your accounting department, since revised editing is not easy.
Your invoice will be sent within a few days by email. My company is identified by VAT number FR74429303332 or French SIRET number 42930333200051, French APE/NAF number 6201Z ("programmation informatique" in French, aka, computer programming).

### Support (back to menu)

For those of you who seek support, contact me, Gilles LAMIRAL, by email or phone:

- Email address: gilles@lamiral.info.
- Desk phone number: +33 9 51 84 42 42 located in France.
- Mobile phone number: +33 6 19 22 03 54 located in France (SFR operator).
- Twitter: https://twitter.com/imapsync

The support is done in English, mostly by email or possibly phone/skype. Office hours start at 10:00, end at 16:00 UTC, extra time is possible in case of emergency. The support aims at helping you to get your imap migration job done, quickly if possible. Support includes things like no time to read the documentation, how to deal with special imap software servers (Gmail, Office365, Exchange etc.), choosing and explaining options, explaining error messages, solving authentication issues, dealing with speed, quotas, special context, running in parallel, etc., so in summary: anything! except doing the job for you.

I have been supporting imap migrations with imapsync since 2001, I still enjoy it!

### Payment by bank transfer and IBAN (back to menu)

If you can't pay with a credit card via Paypal then it is possible to pay via a bank transfer.

Refund for a bank transfer is less easier than with Paypal so drop me an email to test imapsync and to be sure it will do what you need it to do, before any payment.
The bank account references will be given upon request.

It will surely add extra work editing manually the invoice, back and forth getting good coordinates, so I will charge both software and support normal prices for a payment via bank transfer, that is 120 EUR.

### Payment with crypto currencies, Bitcoins, Ethereum etc. (back to menu)

The funny thing about crypto payments is that I receive very few of them, one or two per year, and in small amount, usually one or two dollars equivalent. Maybe one day those little crypto coins will be like gold, I will love that!

My Bitcoin address at coinbase.com is
32C41o5U9W7ewgBmtromsdqNN1cFxLp6k5

Another way is to follow this link at commerce.coinbase.com.
Free price:
https://commerce.coinbase.com/checkout/d757d82d-5f54-428e-9260-90c8b032d7ce

Or 60 euros:
https://commerce.coinbase.com/checkout/5e1ad7cb-dd3d-4cda-bbf1-53d8ba94b7b6

## Facts and figures (back to menu)

- There are 6k imapsync users per month (49k users for the year 2024) Well, if all users could be buyers! (1k == 1000)
- 14M to 21M mailboxes transfers per month during 2024 (M = million = 10^6).
- 203M transfers for 2024, that is 6 whole mailboxes completely synced each second on average (203*10^6/365/24/3600 ~ 6.3), and an estimation of 103 Petabytes transferred in 2024 ( 1 PiB = 2^50 bytes = 1024^5 ~ 10^15), taking a mean of 572 Megabytes per transfer (an estimated mean given by the online /X real stats). 103 Petabytes = 572*10^6*203*10^6. The 2022 global internet traffic was estimated 4200 Exabytes, no evaluation since then. (4200 ~ (273+77) * 12 ) (1 EiB = 2^60 bytes = 1024^6 ~ 10^18) so imapsync is a very very tiny thing, 25 per million (103/4200000).
- Let's see it another way, imapsync did 203M transfers for 2024, that's nearly 803M email messages transferred every day (203*1447/366) taking a mean of 1447 messages per transfer (an estimated mean given by the online /X 2024 real stats). The internet global estimated number of messages sent every day is 362 billions in 2024 (55% being spam but that's another story...). So imapsync does 0.22% (803/362000*100) of all email traffic, not that bad for a command-line tool!
- See the Wikipedia Byte page to learn about Petabytes and Exabytes.
- Operating systems run by command line imapsync users (in 2024):
  - Linux: 64%
  - Win32: 19%
  - Darwin: 17%
  - FreeBSD: 0.18%
  - Solaris: 0.01%
  - OpenBSD: 0.01%
  - Other: 0.01%
  - Cygwin: 0.00%
  - Unknown: 0.00%
- Highest use rate: about 56M IMAP mailbox transfers by just one host (it was in 2014).
- Biggest known sole account migrated: 2.4M folders! (figure independently reported).
- Operating systems run by the visual /X online imapsync users in 2024:
  - Windows 75%
  - Macintosh 19%
  - Linux 5%
  - iPhone 0.14%
  - iPad 0.02%
  - Android 0.03%
  - Debian 0.00%
- Do you notice the reverse statistic pattern between command-line users and visual users?

The figures presented here do not include the GitHub imapsync release usage. It's because --noreleasecheck is on by default in the GitHub release, since release 1.592 (2014/05/22). Looking at the numbers before and after 2014, the figures showed above could be doubled.

Where all those numbers come from? To know whether a newer imapsync exists or not, imapsync does an http GET to the file VERSION. Via the User-agent parameter it also sends:

- imapsync release
- Perl version
- Mail::IMAPClient version
- Operating System

You can remove this behavior by adding the option --noreleasecheck on the command line (or by setting $releasecheck = 0 in the source code). Check CVE-2013-4279.

## How to transfer a single mailbox on Windows (back to menu)

After Imapsync installation, you have to edit a "ready to use" batch file called imapsync_example.bat and run it by a double-click. This batch file is also in the zip archive so it's useless to download it.

I strongly advise you to read and follow the document README_Windows.txt

## How to transfer a single mailbox on Mac (back to menu)

After Imapsync installation, you have to edit a "ready to use" script file called imapsync_example_darwin.bat and run it in a shell window. This script file is also in the tgz archive so it's useless to download it.

I strongly advise you to read first and follow the document INSTALL.Darwin.txt and then the document TUTORIAL_Unix.

## How to transfer a single mailbox on Linux/Unix (back to menu)

Here after is presented a Linux imapsync command line example. You can try it on a terminal, as is. Anyway, it's easier to edit a shell script with the same exact command and run this script in a terminal or from a graphical desktop. Just take the Bourne shell script example imapsync_example.sh and adapt with your own parameters. This shell script file is also in the tgz archive so it can be useless to download it.

I strongly advise you to read and follow the document TUTORIAL_Unix.

After Imapsync installation, a basic example in a shell terminal is the following:

    ./imapsync   \
      --host1 test1.lamiral.info  \
      --user1 test1               \
      --password1  "secret1"      \
      --host2 test2.lamiral.info  \
      --user2 test2               \
      --password2  "secret2"

## How to transfer many mailboxes (back to menu)

In order to migrate many mailboxes, you should use a loop over a csv file containing only the data credentials.
On Windows, see sync_loop_windows.bat batch example.
On Unix, see sync_loop_unix.sh example.
An example of this csv file is file.txt, it can be used with the two previous command scripts.
All example scripts can be found in the examples/* directory.

I strongly advise you to read also the following FAQ documents:

- Migration plan.
- Massive/bulk migrations.
- Admin authentication.

## Installation, Hardware, Operating Systems (back to menu)

Hardware system requirements:

- 500 MB of RAM is ok. The mean value RAM used per imapsync process is 230 MB.
- Any CPU is ok.
- 100 MB of disk space is far enough.
- Any network link is ok. The average bandwidth rate is 345 KiB/s ~ 2.8 Mbps.

Operating System requirements: Imapsync is avalable on Windows, Mac and Linux.
Which Operating System to chose?
Use the Operating System you are the most familiar with.

Location requirements:
Where to place imapsync?
Any host in any place is ok for imapsync as long as it has a network access to both IMAP servers, the source and the destination.

What to do next?
Depending on the system where you will run imapsync:

- Windows users, read directly README_Windows.txt.
- OS X users, read INSTALL.Darwin.txt.
- Debian users, read INSTALL.Debian.txt.
- Centos users, read INSTALL.Centos.txt.
- Ubuntu users, read INSTALL.Ubuntu.txt.
- CPanel users, read INSTALL.CPanel.txt.
- AWS EC2 users, read INSTALL.AWS_EC2.txt.
- WSL users, read INSTALL.WSL.txt.
- ArchLinux users, read INSTALL.ArchLinux.txt.
- AlpineLinux users, read INSTALL.AlpineLinux.txt.
- Suse users, read INSTALL.Suse.txt.
- FreeBSD users, read INSTALL.FreeBSD.txt.
- Docker users, read FAQ.Docker.txt or directly the Imapsync Docker page.
- Online UI sysadmins, wanting their own /X, read INSTALL.OnlineUI.txt
- Other users, read the second part of INSTALL.ANY.txt.
- All installation files are located in the INSTALL.d/ directory.

After the imapsync installation you should go to the documentation section just below.

## Documentation (back to menu)

Windows users, the README_Windows.txt contains essential knowledge to do your first syncs.

Unix users, the TUTORIAL_Unix will teach you smoothly how to do your first syncs. Windows users can read it too.

The README file contains general and specific pieces of information to understand imapsync and succeed in your migration or backup.

The FAQ.d/* files present Frequently Asked Questions (and not so frequently asked ones) and their answers. Here is the main menu, take at least the time to read the menu, you will certainly lose some time to read it, two minutes, but reading this menu will most likely save you some struggling hours later, believe me. So read the three columns main menu:

Specific imap software servers tips

- Dovecot.
- MailEnable.
- Gmail accounts. See OAUTH2 authentication. and Gmail limits.
- Office365. See OAUTH2 authentication.
- Exchange 20xx.
- iCloud.
- Yahoo.
- AOL.
- Domino.
- Zimbra.
- SmarterMail.
- Kerio.
- Cyrus.
- UCS.
- David Tobit.
- Yandex.
- IceWarp.
- DBmail.
- FirstClass.
- MDaemon.
- ProtonMail.
- James.
- Other various imap software servers.

Solving problems (or not...)

- Authentication failure.
- Changing folders names.
- Duplicated messages issues.
- Why use --addheader?
- Passwords on Windows.
- Passwords on Unix.
- Passwords on Mac.
- Flags issues.
- Dates issues.
- Two Ways Sync.
- Memory issue.
- Append errors.
- How to transfer too big messages.
- Contacts and Calendars issues.
- User concurrent access issues.
- Option --usecache and its issues.
- SSL errors.
- Ctrl-c does not end Imapsync.
- Is imapsync a virus?.

Various tips

- Migration plan.
- Massive/bulk migrations.
- Selecting messages.
- Selecting folders.
- Sizes of folders.
- Admin authentication.
- Free email accounts providers.
- Archiving tips.
- Local storage.
- General FAQ.
- Fun things to do with Imapsync.
- Change messages contents with --regexmess.
- POP3 issues.
- Reporting bugs.
- Big mailboxes.
- ISP.
- TTL (MX change in DNS).
- Security.
- Emptying an account.
- XOAUTH2 (Gmail).
- Online Visual Interface (the web GUI /X).
- Principles and design ideas.
- Bandwidth used by Imapsync.
- GDPR (General Data Protection Regulation).
- Using Docker.

The ChangeLog to read what changed in details since 2001.

The TODO file lists what may be coded or done in the future.

All the people I thank are in the CREDITS file.

What you're allowed to do with imapsync is "No limits to do anything with this work and this license." like written in the https://imapsync.lamiral.info/LICENSE file (the detour is worth it).

This document last modified on ($Id: index.shtml,v 1.553 2025/09/25 12:57:41 gilles Exp gilles $)
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