How to Migrate from eM Client to Mailbird: Step-by-Step (2026)

Migrating from eM Client to Mailbird is mostly a sign-in and sync job for server-based accounts. This guide covers the fast route plus the extra steps for Local Folders, POP3, contacts, and calendar.

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Last updated on•
14 min read
Christin Baumgarten

Operations Manager

Oliver Jackson
Reviewer

Email Marketing Specialist

Jose Lopez
Tester

Head of Growth Engineering

Authored By Christin Baumgarten Operations Manager

Christin Baumgarten is the Operations Manager at Mailbird, where she drives product development and leads communications for this leading email client. With over a decade at Mailbird — from a marketing intern to Operations Manager — she offers deep expertise in email technology and productivity. Christin’s experience shaping product strategy and user engagement underscores her authority in the communication technology space.

Reviewed By Oliver Jackson Email Marketing Specialist

Oliver is an accomplished email marketing specialist with more than a decade's worth of experience. His strategic and creative approach to email campaigns has driven significant growth and engagement for businesses across diverse industries. A thought leader in his field, Oliver is known for his insightful webinars and guest posts, where he shares his expert knowledge. His unique blend of skill, creativity, and understanding of audience dynamics make him a standout in the realm of email marketing.

Tested By Jose Lopez Head of Growth Engineering

José López is a Web Consultant & Developer with over 25 years of experience in the field. He is a full-stack developer who specializes in leading teams, managing operations, and developing complex cloud architectures. With expertise in areas such as Project Management, HTML, CSS, JS, PHP, and SQL, José enjoys mentoring fellow engineers and teaching them how to build and scale web applications.

How to Migrate from eM Client to Mailbird: Step-by-Step (2026)
How to Migrate from eM Client to Mailbird: Step-by-Step (2026)

To migrate from eM Client to Mailbird without losing email, add the same email account to Mailbird and let it sync. If the mail you want already lives in server-synced account folders, the switch is mostly a sign-in and sync job. Local-only mail needs extra handling. 3 4 5 7 10

Plan about 20–40 minutes for setup on a typical server-synced account, then extra time for background sync or uploads if the mailbox is large. 22 4

Mailbird on Windows No direct import 20–40 minutes Local-only mail needs extra handling

What’s new

Heads-up for personal Outlook or Hotmail accounts: Mailbird has documented recent Microsoft account authentication failures, and Microsoft has also documented a March 10, 2026 Windows 11 sign-in issue. If login is slow or fails, the blocker may be account authentication rather than message sync. 1 2

TL;DR

Use the path below that matches the data you need to keep.

  • IMAP mail, or Exchange if your plan supports it: Add the same account to Mailbird and let it sync. 4 21
  • eM Client Local Folders: If you need to move email from eM Client Local Folders, copy or move it into an IMAP folder in small batches, verify it in webmail, then let Mailbird sync it down. 7 9 19
  • POP3 or local archive mail: Export .eml files from eM Client and import them into a POP3 account in Mailbird if you want the archive visible there. 6 10 3
  • Contacts and calendar: Let server-synced data appear automatically, or move it with .vcf and .ics files. 6 11 12

If you were hoping for a direct eM Client to Mailbird import, Mailbird’s built-in importer does not currently support eM Client. It supports Thunderbird, Outlook, Windows Live Mail, and IncrediMail instead, and offline files or folders cannot be imported into an IMAP account. 3

Before you start

  • Best platform for this walkthrough: Mailbird on Windows. If you use Mailbird Next, the screens are different, so follow the same IMAP or Exchange-style sign-in logic and confirm the current options in your version before you start. 17 18
  • You’ll need: eM Client still installed, Mailbird installed, your account passwords, any app-password or OAuth prompts your provider requires, and enough free mailbox quota if you plan to upload Local Folders back to an IMAP server. 14 15 19
  • Plan check: If your eM Client account uses Microsoft Exchange, confirm your Mailbird plan supports Exchange before you begin. Mailbird lists Exchange support under Premium. 21
  • Time: About 20–40 minutes for a typical server-synced switch, plus extra sync or upload time for larger mailboxes. 22 4
  • Cost: No third-party converter is required for the routes below; the steps use built-in export/import tools or normal IMAP sync. 3 6
  • Safety: Make an eM Client backup first, and do not remove a POP3 account in Mailbird during troubleshooting unless you have a backup—Mailbird warns that doing so can permanently delete local mail. 6 20

Choose the right route in 30 seconds

Use the fast route if the mail you want is already in server-synced account folders. Use the extended route if you need to move email from eM Client Local Folders, a local Archive, or POP3 downloads. 5 7 8

Fast route

Your account is server-synced—such as IMAP, or Exchange if your Mailbird plan supports it—and the mail you care about lives in regular account folders, not in Local Folders, POP archives, or a local Archive setup in eM Client. 5 7 8 21

Extended route

You use POP3, keep mail in Local Folders or a local Archive, or want older local messages visible inside Mailbird after the switch. That data needs an extra step. 5 7 8

eM Client to Mailbird migration steps

How to Migrate from eM Client to Mailbird: Step-by-Step (2026)

  1. Map what you have in eM Client. Open Menu > Accounts in eM Client and write down each account as IMAP, POP3, or Exchange/EWS. Then check the left sidebar for Local Folders and any local Archive content you need to keep. Check: you finish with a simple list such as “Gmail = IMAP, Work = Exchange, Old ISP = POP3, 3 Local Folders to keep.” 8 7 5

  2. Create a backup before you touch anything. In eM Client, go to Menu > Settings > General > Backup , choose a target folder, and run a backup. Also note the database location in Menu > Settings > General > Storage so you know where the original data lives. Check: you can see the backup folder on disk before moving on. 6

  3. Add the same mailbox to Mailbird instead of looking for a direct eM Client to Mailbird import tool. In Mailbird, open Menu > Settings > Accounts > Add and sign in with the same mailbox you used in eM Client. If automatic detection fails, enter the provider’s IMAP/SMTP or POP3 settings manually. Check: the account appears in Mailbird’s Accounts list and starts syncing or downloading messages. 3 4 10

  4. Leave Mailbird open for the first sync. During initial setup, Mailbird says it downloads and synchronizes emails, attachments, and account data in the background, so large mailboxes can take a while. Don’t judge the move by the first couple of minutes. Check: recent mail opens correctly, folders finish appearing, and sync activity slows down. 4

  5. If the account is server-synced and all important mail is already in account folders, do a quick side-by-side check and move on. Open the same three folders in both apps—Inbox, Sent, and one custom folder—and compare a few dates and message counts. Check: new mail, sent mail, and custom folders line up closely enough that you know the server copy is the one Mailbird is reading. 4 5 8

  6. If you need to move email from eM Client Local Folders and your destination account is IMAP, put that mail back on the server in small batches. Mailbird does not support a direct offline-folder import into IMAP accounts, so the practical workaround is to move or copy a small test batch from eM Client Local Folders into a folder under the same IMAP account, then confirm in webmail that the folder and messages arrived. When the test works, repeat folder by folder until Mailbird syncs them down. Check: each uploaded batch appears in both webmail and Mailbird before you move the next batch. 7 9 19

  7. If you use POP3 or want a local archive inside Mailbird, export mail from eM Client as .eml files. In eM Client, go to Menu > File > Export , choose Export to .eml files , select the folders you want, pick an easy-to-find destination, and finish the export. Check: File Explorer shows a folder full of .eml files before you continue. 6

  8. Import those .eml files into a POP3 account in Mailbird if you want a local archive there. Go to Menu > Settings > Accounts , double-click the POP3 account, click Import messages , choose the .eml files, and wait for Mailbird to place them in an Imported folder. If your destination is IMAP, stop here and use Step 6 instead—Mailbird says offline files or folders cannot be imported into an IMAP account. Check: the Imported folder appears and opens normally. 3 10

  9. Move contacts next. If your contacts are already server-synced through Gmail or Outlook, let Mailbird sync them. Otherwise, in eM Client go to Menu > File > Export > Export contacts to .vcf files ; then in Mailbird Contacts click the gear icon and choose Import contact from vCard . Check: the imported contacts show up as a group in Mailbird. 6 11

  10. Move calendar events only if they are not already syncing from the server. In eM Client, export events to .ics files. In Mailbird Calendar, open the Calendar app, click the gear icon, go to Settings > Import & export , choose the destination account, click Import , and select the .ics file. Check: a few known events appear on the correct dates in Mailbird. 6 12

  11. Rebuild only the rules you actually use. Open Menu > Settings > Filters in Mailbird, choose the account, click Add , and recreate your must-have rules. If you want a rule to sort current inbox mail too, use Save and Run . Check: one test message lands in the right folder and your normal outgoing message uses the right sender and signature. 13

  12. Run a final live test before you uninstall eM Client. Send one email to yourself, send one to another address, reply to one message, search for an older email, and open a few old attachments. Only after that should you make Mailbird your default email app or remove eM Client. Check: send, receive, search, and attachments all work in Mailbird.

Why this works

For IMAP and other server-synced accounts, the real copy of your mail lives on the server, so moving to a new desktop email client is mostly a sign-in-and-sync job. The only data that needs special handling is mail stored only inside eM Client—especially Local Folders, POP3 downloads, and other local-only archives. 4 5 7 8

Troubleshooting

Mailbird says “Nothing to import”

Likely cause: Mailbird could not detect a supported old profile, or you’re trying to use the built-in importer for eM Client.

Fix: Skip the import button, add the mailbox manually, or export .eml from eM Client and import that into a POP3 account instead. 3

Old folders are missing after sign-in

Likely cause: Initial sync is still running, or IMAP is disabled at the provider.

Fix: Leave Mailbird open longer, then check your provider’s IMAP setting and re-add the account if needed. 4 14

Outlook/Hotmail will not authenticate

Likely cause: OAuth or IMAP settings are wrong, or you’re hitting the recent Microsoft account sign-in problems Mailbird documented.

Fix: Use OAuth2 when available, make sure IMAP is enabled in Outlook settings, and if the problem started after the March 10, 2026 Windows update, check Microsoft’s published guidance for the KB5079473 sign-in issue. 1 2 14 15

You get “host not found” or DNS errors

Likely cause: Wrong server name, VPN/proxy interference, firewall blocking, or a temporary network problem.

Fix: Double-check the incoming and outgoing server names, disable the VPN, and try another network if needed. 16

Mail shows in Mailbird but not on your phone or second PC

Likely cause: You’re using POP3, which stores mail locally instead of syncing it across devices.

Fix: Switch to IMAP for normal day-to-day use, or keep POP3 only as a local archive route. 5 10

Imported contacts seem missing

Likely cause: Mailbird adds imported vCard contacts as a group instead of merging them into every account automatically.

Fix: Look for the new contact group in Mailbird Contacts, or let Gmail/Outlook contacts sync from the server instead. 11

Filters did not sort older email

Likely cause: Mailbird filters only run while Mailbird is open.

Fix: Edit the rule and use Save and Run so it applies to existing inbox mail too. 13

You removed a broken POP3 account and worry about data loss

Likely cause: POP3 may have been holding the only local copy of some messages.

Fix: Restore from backup if possible, and next time back up first or contact support before removing a POP3 account. 20 6

Common migration scenarios

  • Fastest switch: If everything is server-synced and there is no local-only mail to save, just add the same account to Mailbird, let it sync, and test send/receive. 5 4
  • Safer Local Folders move: Create one IMAP folder called something like “Uploaded from eM Client,” upload a small test batch there first, then split the rest into manageable chunks so you can verify each batch and watch your provider quota. 9 19
  • Local archive route: Export mail from eM Client as .eml , then import it into a POP3 account in Mailbird if you want an offline archive visible inside Mailbird itself. 3 6 10
  • Mailbird Next route: The screens are different, but the same IMAP or Exchange-style sign-in logic applies. Confirm the current options in your version before you start. 18

Plan large or multi-account moves

  • Make-ahead: If you have a big mailbox, export .eml , .vcf , and .ics files the day before. That turns switch day into mostly sign-in and sync. 6
  • Storage: Keep your eM Client backup and any exported files until Mailbird has survived a few normal workdays. If you upload Local Folders back to IMAP, the limiting factor is your provider’s mailbox quota, not Mailbird’s own storage limit. 6 19
  • Scaling: Migrate one account first, especially if you manage several mailboxes or an Exchange account. Once the first account sends, receives, searches, and syncs correctly, repeat the same sequence for the rest. If you use Exchange, confirm your Mailbird plan first. 21

What can change

Import support, OAuth rules, Windows compatibility, and Mailbird Next options can change. If a screen in this guide does not match what you see, verify the current import support list, your provider’s IMAP or OAuth requirements, and your Mailbird platform before deleting anything. 3 14 15 17 18

Related

Frequently Asked Questions

Does Mailbird have a direct eM Client to Mailbird import?

No. The practical path is to add the same mailbox to Mailbird, then move any local mail, contacts, or calendars separately.

Sources: 3 6 11 12

Will I lose my email if I switch from eM Client to Mailbird?

Usually not for IMAP or other server-synced accounts, because the mail is already on the server. The risky cases are POP3 mail and Local Folders, which need backup, export, or server upload first.

Sources: 5 7 8 20

Can I move eM Client Local Folders into Mailbird?

Yes, but not as a direct IMAP import. Move or copy that mail into an IMAP folder first, or export it as .eml and import it into a POP3 archive account.

Sources: 3 6 7 9 10

How do I move contacts and calendar events?

Contacts can sync from Gmail or Outlook, or you can export .vcf from eM Client and import it in Mailbird. Calendar events can move with .ics files.

Sources: 6 11 12

Do rules and filters transfer automatically?

Assume no. Recreate the rules you actually need in Mailbird and test them with a live message.

Sources: 13

Can I do this in Mailbird Next?

Yes, but the screens are different. Use the same IMAP or Exchange-style sign-in logic and confirm the current options in your version before you start.

Sources: 18

How long does the switch usually take?

Plan about 20–40 minutes for setup, then extra time for background sync or upload if the mailbox is large.

Sources: 22 4

Do I need a third-party converter?

No for the routes in this guide. Standard account sign-in, .eml export, .vcf contact export, and .ics calendar export are enough.

Sources: 3 6 11 12

Quick checklist

  • I backed up eM Client before changing anything.
  • I wrote down each account as IMAP, POP3, or Exchange/EWS.
  • I added the same mailbox to Mailbird and waited for first sync.
  • I checked whether any mail lives only in Local Folders or old POP archives.
  • If needed, I copied local mail to IMAP or exported it as .eml .
  • If needed, I moved contacts with .vcf .
  • If needed, I moved calendar events with .ics .
  • I rebuilt the few filters I actually use.
  • I tested send, receive, search, and attachments in Mailbird.
  • I kept my eM Client backup and did not uninstall until everything checked out.

Sources

  1. Mailbird Support — Fix Microsoft Outlook / Hotmail Authentication Failures in Mailbird
  2. Microsoft Support — March 10, 2026 KB5079473 known issue for Microsoft account sign-ins
  3. Mailbird Support — How to Import Accounts and Emails to Mailbird
  4. Mailbird Support — IMAP Support in Mailbird
  5. Mailbird Support — What is the difference between IMAP and POP3?
  6. eM Client Documentation PDF — Backup, export, and storage
  7. eM Client FAQ — What are “Local Folders” in eM Client?
  8. eM Client FAQ — Getting Started (mail services, account types, archive behavior)
  9. Mailbird Support — How to import Local Folders from Thunderbird to Mailbird
  10. Mailbird Support — POP3 settings
  11. Mailbird Support — Importing and exporting a contact group and individual contacts
  12. Mailbird Support — Import & Export Calendar
  13. Mailbird Support — Setting up Filters and Rules
  14. Mailbird Support — How to enable IMAP for your email account in Mailbird
  15. Mailbird Support — Troubleshooting Authentication Issues in Mailbird
  16. Mailbird Support — No internet connection or DNS lookup failed while adding an account
  17. Mailbird Support — What versions of Windows are supported by Mailbird?
  18. Mailbird Next Support — How to Check if Your Email Account Is Using IMAP or Exchange in Mailbird Next
  19. Mailbird Support — Is there a data storage limit in Mailbird?
  20. Mailbird Support — Server authentication failed
  21. Mailbird Support — Key differences between our licenses
  22. Mailbird Blog — How to migrate from Thunderbird to Mailbird without losing any email