Large-scale migration with no lost data

How Credit Suisse, Harvard University and HP migrated millions of emails quickly, reliably and accurately

If you need to process less than 50 user accounts, please visit our regular “Email Migration” page.

Migrate 16,000+ Emails Per Account Every Minute

Install Aid4Mail this Friday afternoon, and by the time you return to the office on Monday morning, you could have as many as 45,000,000 emails migrated. Start by using this calculator to estimate your migration time…

Average processing speed:

(*) These tests were performed on a 5-year old PC with a Quad-Core Intel Xeon processor under the 64-bit edition of Windows 7 and the 32-bit edition of Outlook 2010. Internet speed was 75 Mbit/s for downloads and 7 Mbit/s for uploads.
DISCLAIMER: your results may vary significantly from ours. Many factors influence processing speed.

Want a more accurate estimate?

Use our Large-Scale Migration Throughput formula to determine how long your entire migration will take with Aid4Mail.

Download it now

Why You Should Choose Aid4Mail For Your Migration


Saves time, thanks to its fast conversion engine and batch processing options.


Saves money, thanks to competitive pricing.
Skip to pricing »


Makes your life easier, since you can easily run it from servers and USB flash drives. No need to install on each computer.


Gives you peace of mind, because it’s so accurate and reliable.


Satisfaction guaranteed, with speedy support and quick fixes when issues arise.


Data security assured, as you are in complete control of your data with this on-premise solution.

Download our whitepaper Migrating Corporate Email: 7 Things to Look for in a Migration Tool to learn more about essential requirements for any migration solution.

Want to know why Aid4Mail is faster and more secure than cloud-based migration solutions?

Migrating your mail from Outlook to Office 365? Or from Thunderbird to Google Apps? An on-premise solution like Aid4Mail will be faster and more secure than a cloud-based solution. Here’s why:

  • Data security: Your data is going from your own servers, directly to your chosen email provider. There are no middle-men servers in undefined locations to compromise the security of your sensitive data.
  • Faster conversion: With Aid4Mail, the mail conversion is done on premise and then uploaded. With cloud vendors, your mail is uploaded, converted and only then sent to your new email provider. You save a whole step with Aid4Mail.
  • Complete control: Know exactly what is happening with your migration every step of the way. Mitigate any issues as they arise, instead of after all your mail has already been migrated.

Download our whitepaper Migrating Corporate Email: What to Resolve Before You Start to learn more about how to perform cloud migrations.

“Even with large mail files, Aid4Mail produced problem-free exports in a few seconds.”

– PC Magazine, USA

Supports 40+ Email Formats and All Popular Webmail Services

Migrate your email to Office 365 or Google Apps, or to Outlook and Exchange. Aid4Mail is the ideal solution for large corporations, government agencies and universities.

With some customers migrating over 60,000 email accounts to Office 365, you can be sure Aid4Mail is a proven, enterprise grade email migration solution.

Is your messaging system not listed above? See all supported formats.

Affordable, Blazingly Fast – and Your IT Team Won’t Have to Spend Their Weekend in the Office

Migrate 5x Faster* with Aid4Mail Console Launcher

Do you need a way to easily manage a large migration? Our new, user-friendly utility, Aid4Mail Console Launcher is included with your purchase of Aid4Mail Migrator.

  • Speed up your migration by 500% by concurrently migrating accounts from a single CSV file
  • Schedule your migration for over the weekend or in office down-time
  • Get key progress information by email for total peace of mind

* Comparison between a single 186MB MBOX to EML conversion, and 12 concurrent 186MB MBOX to EML conversions using Aid4Mail Console Launcher. This test was performed on a 64-bit Windows 10 PC with 8GB RAM and an Intel Core i5-6500 CPU at 3.2 GHz.

Empower your team to migrate their own mailboxes

Do you want your end-users to manage their own migration? Aid4Mail can run from each end-user’s computer and offers users a friendly wizard- style interface (GUI) that even the least tech- confident person in your workplace will use easily.

Comprehensive context-sensitive instructions - included at every step of the way - provide all the info your end users need to complete their migration smoothly.

Unlimited possibilities with our Command-Line Interface

Do you have advanced requirements that require the utmost flexibility? Aid4Mail Console is also included with your purchase of Aid4Mail Migrator. The Console offers a command-line interface (CLI) with unlimited scripting and integration possibilities.

Need some help? We can provide you technical assistance for your project. Just let us know what you want to achieve.

Contact us with your requirements

Get easy, clear reporting at each step of your migration

Let Aid4Mail run overnight or over the weekend. We’ll send you key progress information by email for your peace of mind. And errors are carefully logged so you know exactly how well email accounts have migrated.

No data loss! We preserve rejected data

Let’s say an email you’re migrating exceeds IMAP size limits. Simply tell Aid4Mail to remove its attachments and store them locally. It will then upload the trimmed-down email.

That’s just one example of the many fail-safes we’ve built into Aid4Mail.

Want to learn more? View our Aid4Mail Feature Comparison Chart to see exactly what’s included in Aid4Mail Migrator

Aid4Mail Has Successfully Migrated Millions of Mailboxes Worldwide

Aid4Mail has been downloaded more than 100,000 times for small and large-scale needs. Built and supported in Switzerland, Aid4Mail is used in 120+ countries.


“Aid4Mail is a spectacular product. I don't think people realize how hard it is to reliably convert email from one format to another, and then do it at scale the way you do. It really is quite an accomplishment.”
– Matt Coan, Sonian          [ Read our Sonian Case Study ]


“Using Aid4Mail for our data migration from thousands of IMAP mail stores to the MS Live [Office 365] environment, the process has been smooth and fast.”
– Peter Hopkin, University of London


“I was also fascinated with the fact that Aid4Mail churned through my mail without crashing, stuttering, or spitting out any error messages: it just simply did the job.”
– Chris Jenkins, Implexant Systems


“We work with over 1TB [one terabyte] of email per month and your Aid4Mail product has shown to be an integral part of our toolset for dealing with these volumes of email.”
– Jason Rappoport, Capsicum Group

Try Aid4Mail Migrator Today

Take advantage of our free trial to see how Aid4Mail Migrator could work for your large-scale email migration.

  • No credit cards
  • No obligations
  • Process unlimited emails
  • Test for as long as you like

Once you have registered for the free trial, you’ll also be sent exclusive resources to help you plan and execute your migration as efficiently as possible.

Register for your free trial

Migrating Remote Accounts Instead?

Don’t worry. We have a solution for you too. Aid4Mail Site is installed on each end-user’s computer so they can manage the migration themselves.

You’ll only need one activation code for all users, and you’ll be able to see who has activated their licenses through our Online License Control Panel.

Already Know Aid4Mail is Right for Your Migration? Get it Now.

Thank you for choosing Aid4Mail. Please note that you need to get as many seats as the number of you want to migrate. So to process the mailboxes of 75 employees you need to purchase 75 seats. See our EULA for the details. You can set the number of seats on the next screen.

Aid4Mail Migrator
Migration by IT staff

  •  Runs from server or thumb drive
     Valid from two months up
     Offline license key file
     Free priority customer support
  •  Aid4Mail Console Launcher
     Wizard (GUI) + Command line (CLI)
     Concurrent migrations
     Email Progress Notifications
     All account settings in one CSV

Aid4Mail Site
Migration by end users

  •  Runs from end-user's computer
     One-year license
     One activation code per site
     Free priority customer support
     50% discount on renewal
     Wizard (GUI)
     Online License Control Panel
     Can be used for long-term archiving

Double-check the system requirements here…

  • Operating System : Aid4Mail runs under Windows 10, 8, 7, Vista, XP, 2000, Server 2016, 2012, 2008 and 2003 or Linux in conjunction with Wine. Both Windows 32-bit and 64-bit are supported.
    Windows NT4 / ME / 98 / 95 should work but are not officially supported.
  • Internet : Online license activation, validation, and re-activation require an internet connection (offline activation option available with Aid4Mail eDiscovery editions).
  • Hardware Requirements : 64 MB of RAM, 12 MB disk space. Pentium (or compatible) processor.


Aid4Mail can read mail from:

  • Microsoft Exchange through Outlook/MAPI (1) (except Aid4Mail Home) or IMAP (2),
  • Outlook Personal Storage files (1) (*.pst),
  • Outlook MSG files (1) (*.msg),
  • Outlook Express versions 5 and 6 (*.dbx, *.eml and *.nws),
  • Outlook Express version 4 (*.idx and *.mbx),
  • Windows Live Mail (*.eml;*.nws),
  • Windows Mail (Vista mail client),
  • IMAP accounts,
  • Webmail services that offer IMAP access, e.g. Gmail, Yahoo! Mail, AOL Mail, FastMail, GMX Mail,, Outlook 365, etc.,
  • Mozilla Thunderbird mailbox files,
  • SeaMonkey mailbox files,
  • Netscape mailbox files,
  • Apple Mail ( message files (*.emlx),
  • Qualcomm Eudora mailbox files (*.toc and *.mbx),
  • Eudora OSE mailbox files,
  • Macintosh Eudora mailbox files,
  • Google Takeout files (*.mbox),
  • Google Vault files (*.mbox),
  • Generic mailbox files (mbox, Entourage MBOX, Evolution, Berkeley mail, BSD mail, Unix mail format),
  • EML message files (*.eml),
  • MHT Web Archive files (*.mht),
  • Pegasus mailbox files (*.pmi, *.pmm, and *.cnm),
  • The Bat! mailbox files (3) (*.msb and *.tbb),
  • PocoMail mailbox files (*.idx, *.idb, and *.mbx),
  • Barca mailbox files (*.idx, *.idb, and *.mbx),
  • FoxMail mailbox files up to version 6.5 (*.box),
  • Opera mailbox files (*.mbs),
  • Calypso and Courier archive files,
  • Forte Agent mailbox files (*.idx),
  • Pine mbox files (with limited “From ” escaping),
  • PMMail message files (*.msg),
  • Maildir folders (local copies),
  • MSN Mail v8 (*.MailDB),
  • Mailbag Assistant mailbox files (*.mbg),
  • E-mail Examiner mailbox files (*.pmx),
  • Aid4Mail ZIP archives (*.zip).

Aid4Mail can export/save mail to:

  • Microsoft Exchange through Outlook/MAPI (1) (except Aid4Mail Home) or IMAP (2),
  • Outlook Personal Storage files (1) (*.pst),
  • Outlook MSG files (1) (*.msg) – only if source mail comes from Microsoft Exchange or Outlook files,
  • Windows Live Mail,
  • Windows Mail (Vista mail client),
  • IMAP accounts,
  • Webmail services that offer IMAP access, e.g. Gmail, Yahoo! Mail, AOL Mail, FastMail, GMX Mail,, Outlook 365, etc,
  • Mozilla Thunderbird mailbox files,
  • SeaMonkey mailbox files,
  • Eudora OSE mailbox files,
  • Netscape mailbox files,
  • PocoMail mailbox files (*.mbx),
  • Barca mailbox files (*.mbx),
  • Generic mailbox files, (mbox, Entourage MBOX, Evolution, Berkeley mail, BSD mail, Unix mail format),
  • EML message files (*.eml),
  • XML files (*.xml),
  • Plain text files (*.txt),
  • MHT Web Archive files (*.mht) - linked from an HTML index page or an MS Excel Workbook file (not available in Aid4Mail Home),
  • MHT files with tab-delimited data file for import into a database (not available in Aid4Mail Home),
  • Adobe Acrobat PDF files (not available in Aid4Mail Home),
  • Aid4Mail ZIP archives (*.zip).


  1. To process (from/to) Outlook MSG files, PST files, and Outlook/MAPI mail profiles, Aid4Mail requires either a 32-bit version of Office Outlook or a standalone version of MAPI. For details, free options, and limitations, see the System Requirements.
    Only Aid4Mail Console can export a source MAPI profile or PST file to a target MAPI profile or PST file. With Aid4Mail Home, Aid4Mail Professional, and Aid4Mail eDiscovery, the workaround is to first export your emails to the Outlook MSG format, and then re-export those files to your target format.
  2. Microsoft Exchange can either be processed through an Outlook/MAPI mail profile (1), or through the IMAP protocol in which case the Exchange server needs to be set up for IMAP access (see instructions).
  3. Aid4Mail cannot process encrypted The Bat! mail files. In this case, you will first have to export your messages with The Bat! to a Generic mailbox format, which Aid4Mail can then process to any of the supported formats.
  4. Aid4Mail currently does not offer tools to convert address books, filters, or account settings from one format to another.