Email Migration: Frequent Questions

Frequently asked questions concerning the email transfer, features, subscriptions & pricing of the MailJerry app


What types of Mailboxes are supported?

MailJerry supports all types of IMAP and Exchange based mail servers. Since IMAP is the worlds most used email protocol, MailJerry is compatible with nearly every provider and server, including email providers like Gmail, Microsoft 365, Yahoo!, GMX or GoDaddy.


To sum it up:

  • IMAP: Full support including email status and flags (e.g. read, unread…).
  • Exchange: Full support, in rare cases some flags are not fully supported.
  • POP: Only recommend if your account is set up to store a copy of your email on your mail server.

Does MailJerry work with Gmail?

Yes, MailJerry is compatible with Gmail. However, in order to be able to establish a connection, you must change the settings of your account. For details, see Transferring Emails from or to your Gmail Account.

Does the app work with Outlook?

Yes, if you chose „IMAP“ in your account settings, MailJerry can migrate your emails from or to the email address registered in Outlook.

I have an Exchange account. Can I use MailJerry to transfer my mailbox?

Of course! MailJerry is compatible with all exchange accounts.

Can I use the Exchange admin / tenant password to migrate all mailboxes?

No. To migrate an entire tenant, you need the password of every single mailbox. The tenant / admin password is not sufficient, as it does not grant MailJerry access to the email data of the individual mailboxes.

What is IMAP?

IMAP („Internet Message Access Protocol“) is a protocol that allows you to store your emails on a mailserver. This means, that your email data is not stored on your computer or mobile device, but on a server. Thanks to IMAP, you can access the same emails on multiple devices.

Does the app work with POP accounts?

Our IMAP email migration tool also supports POP based mailboxes, as long as a copy of your email is stored on your mail server. If your POP account is configured to delete your emails from the mail server, you unfortunately cannot use MailJerry.

Does MailJerry work with all email providers?

Sure, as long as you are using IMAP for your account, MailJerry works with all providers.

Your Email Migration

Can I only transfer parts of my mailbox or a selection of emails?

At the moment, MailJerry migrates all data contained in your mailbox. If you wish to transfer only a selection of emails, we kindly ask you remove all unneeded emails from your current mailbox (e.g. store or archive the data locally or copy the emails to a POP account).

My new mail box already contains emails. Can I still use the app?

Of course! Before each migration, MailJerry performs a health check and checks whether your mailbox already contains data. If so, you will be informed and can cancel the migration or let MailJerry add the emails to the receiving mailbox. Emails that are already contained in the receiving inbox will under no circumstances be deleted.

My mailbox is extremely large. Is there anything I can do to reduce the data amount?

There are several ways to reduce the size of your mailbox before starting your email migration with our email migration tool:

  • archive or delete large attachments (e.g. large image files, PDFs, Word documents etc.)

  • archive old emails locally on your computer or store them in a POP mailbox

  • delete files contained in the trash of your mail program

  • delete all data or parts of the „send messages“ folder

I need to migrate my emails to a new server but I want to keep my email address and domain. Can I use MailJerry to do so?

Yes. MailJerry can connect with your old and new mail server, even if you want to keep the same email address and domain.


For the mail server that is not connected with your domain (usually the new mail server), simply enter an alternative mail server name (if provided) or the IP address of your mail server. In case you don’t know the IP address or if an alternative mail server name (e.g. is available, contact your email provider / hosting company.


Next, simply enter the IP address or alternative host name in the field “mail server” and start your migration!

Does MailJerry sync my accounts after the email migration?

Yes, if you activate the option „Sync my Emails“ in the MailJerry app, all emails received in your old mailbox will be automatically migrated to your new mailbox after the transfer. The email sync is available for all paid licenses.

Subscription customers can sync mailboxes for a period of up to 10 days. Of course, you can deactivate the sync any time.

Does MailJerry copy contacts?

No. MailJerry uses the IMAP protocol to access and copy emails. Unfortunately IMAP does not support contacts at all.

I have many mailboxes to transfer. Can I run them simultaneously?

Yes, MailJerry supports unlimited parallel migrations.

Just start a new transfer at any time, your existing migrations will stay active.

What does the simultaneous migrations limit mean? Do I have to wait?

Depending on the license type, you can only run a certain number of email migrations simultaneously. However, you can start an unlimited number of email migrations. The simultaneous migration limit does not affect the number of migration you start, only how many migrations are performed simultaneously.

➡️ After you reached the simultaneous migrations limit, further migrations will be queued and start automatically.

Example: Your wish to migrate 34 mailboxes and your license includes 10 simultaneous migrations.
This means that the first 10 mailbox migrations will start immediately, the remaining migrations will be queued and start automatically as soon as one of the 10 initial migrations finished.


Are my emails downloaded to my computer during the email migration?

No. MailJerry migrates your data directly between your mail servers. Your emails are not stored on our email migration cloud and not downloaded to your device.

My internet connection is very slow / has bandwidth restrictions. Can I use MailJerry anyway?

Of course – that’s one of the huge advantages of our cloud based email migration tool! MailJerry manages your data migration in our email migration cloud and migrates your data directly between your mail servers. So, MailJerry does not use your internet connection / bandwidth for the data migration


Therefore, it’s absolutely safe to use MailJerry for your email migration, even with limited bandwidth and / or with an unreliable internet connection.

Can I close MailJerry / shutdown my PC or will my active migration break?

MailJerry is a cloud based email migration service. This means: Once you’ve started your migration, you can shut down the software and / or your computer. The email migration is performed on our email migration cloud, so it will continue to run, even if you shut down the software.


Pro tip: If you want to check the status of your email migration on the go, download the MailJerry app for Android or iPhone, enter your license key and monitor the progress of your data migration, even if you’re not in front of your computer.

How long does MailJerry keep my migrations?

Once your migration is completed, it will be deleted after some time of inactivity. Inactivity means that

  • the autosync is disabled and
  • the backup mode is disabled and
  • no recent syncs where performed

By default, inactive migrations will be kept for 1 month. If you prefer to keep your migrations longer, you can change this option in “Settings → Migration Settings → Delete Finished Migrations After”.

Mailbox Synchronization

Can I synchronize my mailboxes after the mailbox migration?

Yes! The email sync is available for all customers with a valid subscription.

How can I enable the mailbox sync?

After the migration, go to „Overview“ and click on the migration you wish to synchronize. Below the migration details, you’ll find the section „Settings“ where you can enable the option „Synchronize Emails“.

After you enabled the sync, all new emails received in your old mailbox will be automatically transferred to your target mailbox.

The sync is performed every three hours for a maximum duration of 10 days.

How often are my mailboxes synced after I enabled the email sync feature?

If you enable the option „Synchronize Emails“ for your migration, new emails will be migrated every three hours.

The sync stops after 10 days or after you disable the sync for the individual migration.

How does the backup mode work?

If you activate the backup mode in MailJerry, your target mailbox will be permanently synchronized with your source mailbox. This means that the target mailbox is used as a backup mailbox. You can use any IMAP mailbox as backup target, also free services like Gmail or Yahoo.


The advantage of this kind of backup is that you can access your backup any time and from any device.

MailJerry creates duplicates during each sync. What can I do?

When receiving a new email, some mail servers change the header of the received email. In this case, MailJerry is not able to detect duplicates correctly.


If this happens, go to “Settings → Migration Settings → Email Header Settings” and select the option “Message-ID”.


Now, clear your target mailbox and start the mail migration again.

Does MailJerry work with Gmail?

Yes, MailJerry is compatible with all Gmail accounts. However, you have to change your Gmail security settings to allow access to your account.


After you entered your credentials in the app, MailJerry will provide you with a simple step-by-step tutorial explaining how to change these settings.

My migration to or from a Gmail account is extremely slow. Is this normal?

When transferring large mailboxes, you might exceed the Gmail bandwidth limits:
Downloads: 2500 MB per day
Uploads: 500 MB per day

In this case, your mail migration might become extremely slow or pause temporarily. Please do not stop the email migration if you encounter this issue. It is no problem at all if your migration runs longer than 24 hours.

While your email migration is running, you can use your mailboxes as usual. To migrate emails you received during the transfer, simply activate the mailbox sync in the MailJerry App.

For details about Gmail bandwidth limitations, see

After the email migration, my Gmail accounts do not have the same file size. How is this possible?

When migrating email data from one Gmail account to another, the size of the mailboxes may vary after the migration is completed.
The size of your Gmail account results from your email data and various other data types (e.g. metadata, chat logs, hangout history ...). This data is added to the size of your mailbox, but not transferred.
Therefore, if the size of your mailboxes varies, there is no need to worry. In any case, your e-mail data will have been migrated to your new e-mail address.

Why does MailJerry show a wrong message count and mailbox size for my Gmail mailbox?

Gmail stores content like labels, custom directories and categorised emails as symlinks (= links to the original content). This content adds up to the total message count in your Gmail account.


MailJerry is not able detect this content during the mailbox check and can show a wrong message count. During the migration, symlinks are skipped, because otherwise, there would be duplicates in your new mailbox.

Why does the number of migrated emails differ between Gmail and my other mailbox?

The number of messages shown in your Gmail account may vary if one or both of your accounts group your emails by conversations. Please turn off the conversation view in Gmail to receive more precise results.

Why are emails skipped when migrating from Gmail to my other mailbox?

Gmail stores content like labels, custom directories and categorised emails as symlinks (= link to the original content). This content adds up to the total message count in your Gmail account. During the migration, symlinks are skipped, because otherwise, there would be duplicates in your new mailbox.

For example:

There are five emails with the label „important“ in your Gmail account. When checking your mailbox, Google informs us that there are 10 emails in the account (5 original emails + 5 symlinks that add the label „important“).


If you migrate from Gmail to another provider, the new provider cannot handle symlinks, as this way of storing additional information is only used by Gmail.


That’s why, in this example, 5 emails are migrated (= the actual, existing emails), and 5 are skipped (= the symlinks).


If we didn’t skip the 5 symlinks, your mailserver would create a duplicate for every symlink (create original email, get symlink info > follow symlink > create email again).


To get more accurate data bout the message count in your Gmail account, disabled the conversation view in Gmail. This might get closer to the real message count. However, differences may still occur.


All that said, rest assured that MailJerry will migrate every single real email that is found in your Gmail account and not already migrated to your new mailbox.

Do you provide a tutorial on how to migrate emails from / to Gmail?

Yes! Have a look at our comprehensive Gmail migration tutorial.

Microsoft / MS 365 / Exchange Online

Does MailJerry support OAuth2 for Microsoft / MS 365?

Yes. MailJerry provides a preset to start migrations from or to Microsoft accounts.


Simply select Microsoft / Office 365 as account type, enter your Microsoft username and click on “Connect with Microsoft Account”. Now enter your password to connect with your Microsoft account.

Can I use MailJerry to migrate from one Microsoft account to another?

Yes. Please select Microsoft / Office 365 as account types for both mailboxes and follow the instructions.


💡 For best compatibility, please ensure that both Microsoft mailboxes are configured in the same language!

After the migration to MS 365, my sent items, drafts and deleted items folders are missing. What can I do?

Usually, this happens if the folders of the source and target mailbox are not using the same language.

Please change the language of your MS 365 mailbox to English and start the migration again.

➡️ Every email / folder that has already been migrated during the first migration will be skipped. You should be able to see your drafts / sent / deleted items folders after the second migration finished.

Can I use MailJerry to migrate from Gmail / Google Workspace to Microsoft / MS 365?

Yes. Please select Gmail as source account type and Microsoft / Office 365 as target account type and follow the instructions to connect with your accounts.

Why is my migration from or to Microsoft / MS 365 so slow?

The speed of your migration depends on the capabilities of your source and target mail servers.

Since Microsoft has a limitation of 3,600 messages per hour, it’s possible that your migration is throttled down by the Microsoft servers after the maximum is exceeded. You can find more information about Microsofts limits here.

How can I change the language of my Microsoft / MS 365 mailbox?

For best compatibility, we recommend to switch your mailbox language to English during the migration. This ensures that default folders like “Sent Items”, “Deleted Items” and “Drafts” can be assigned correctly between both mailboxes.


➡️ Click here to learn how to change the language of your Microsoft mailbox.

On-Premise Exchange

Can I use MailJerry to migrate emails from or to On-Premise Exchange servers?

Yes! If your server supports OAuth2 over, you can use the Microsoft / Outlook 365 preset in MailJerry.

Otherwise please use IMAP as account type and enter the address of your Exchange server.

What are the requirements for an Exchange migration?

MailJerry uses the IMAP protocol to perform a mailbox migration. To start a migration, please ensure that IMAP is enabled in your On-Premise Exchange mail server.


Please also ensure that your firewall settings are configured to allow connections on your IMAP port (143 or 993).

Bulk Migration

Does MailJerry support mass migrations / bulk migrations?

Yes. MailJerry includes a bulk migration feature for all yearly subscriptions.


ℹ️ Currently, bulk migration is available as Beta only in the web app.

What types of bulk migrations are available?

MailJerry supports bulk migration by direct input or CSV upload:

  • Direct Input: Directly enter the access data of the mailboxes you wish to migrate. This is the fastest solution to start some or many migrations from one server to another at the same time
  • CSV Upload: The fastest solution to start a huge amount of mailbox migrations simultaneously.

How does the bulk migration work?

  1. First, enter the name of the source and target mail server.
  2. Now, add the mailboxes you wish to migrate by directly entering the access data or using the CSV upload.
  3. Click on “Check Mailboxes” and wait until all mailboxes are checked.
  4. After all credentials were checked successfully, you can start the bulk migration by clicking on “Start Migrations”.

How many migrations can I start at the same time?

Bulk migrations are not limited. This means that your bulk migration can include hundreds of mailboxes.


Depending on your MailJerry settings and your license type, up to 20 migrations can be performed simultaneously, while the remaining mailboxes are queued. If one migration is finished, the next in line starts automatically.

Can I upload a CSV file to start a bulk migration?

Yes. Please download the CSV template here and insert the source and target login credentials for each mailbox.


Upload the CSV file in MailJerry in Bulk Migration → CSV upload. Now, you only have to enter the source and target mail server and can start the bulk migration.

Can I perform a bulk migration from or to Gmail or Google Workspace?

Yes. Please create an app password for every Gmail / Google Workspace mailbox and use it instead of the default user password.


Also, make sure that IMAP access is enabled.

Can I create a bulk migration for Microsoft / MS 365 / Office 365 mailboxes?

This depends on your account type. The bulk migration does not support OAuth2 yet. To perform a bulk migration from or to MS 365, it’s required to use Basic Authentication. Unfortunately, Microsoft hast disabled Basic Authentication for most accounts starting January 2023.


However, if your MS 365 tenant still supports Basic Authentication, you can use the bulk migration by creating an app password for each user.


➡️  Please create a single migration using the IMAP preset and as mail server and check if a connection to your account is possible. If the connection is successful, you can migrate all mailboxes of the same type using the bulk migration.

Does the bulk migration support Microsoft OAuth2?

Not yet. In order to migrate from or to MS 365 using OAuth2 as login method, it’s required to create a single migration for each mailbox. Your migrations will still run simultaneously, but you have to start them one after another.

Can I start a bulk migration from or to Yahoo?

Yes. Please use as mail server and follow the instructions to create an app password for each Yahoo! account.

Why is the bulk migration not available for my monthly subscription?

The bulk migration feature provides a convenient way to transfer many mailboxes simultaneously. By nature, running bulk migrations requires more bandwidth and server performance than single migrations do.


Although all MailJerry subscriptions are unlimited, we need to cover the higher costs that are caused when running bulk migrations. Therefore, bulk migrations are only available for yearly subscriptions.

Pricing & Plans

How much does my email migration cost?

You can migrate email addresses up to a data volume of 250 MB free of charge. For larger data volumes, you can choose between a monthly or annual subscription. You can find our prices here.

I would like to migrate email addresses once. Which license do I need?

In this case we recommend our monthly plan. You can find an overview of our prices here.

I would like to migrate email addresses once for several days. Which license is the right one?

For the one-time migration of one or more mailboxes over a period of several days, we recommend our monthly subscription. You can cancel the subscription immediately after the purchase or the completion of the email transfer and only pay the monthly fee once. You can find an overview of our prices here.

I regularly migrate a lot of mailboxes. How can I save?

If you use the MailJerry email migration service frequently, we recommend our annual subscription. You benefit from the same advantages as when using the monthly subscription (unlimited data volume, unlimited transfers) and save compared to monthly payments. You can find an overview of our prices here.

Which subscription is best for me?

If you migrate individual mailboxes only once or over a period of multiple days, our monthly subscription is a convenient and inexpensive solution. You only pay for one month in advance and can cancel the subscription at any time.

Professional users (e.g. IT technicians, IT administrators, providers) who want to use MailJerry regularly benefit from the discounted conditions of our annual subscription.

You can see the prices in detail here.

Does my subscription include unlimited traffic?

Yes, all paid options include unlimited traffic and unlimited parallel transfers.

How can I upgrade my subscription?

If you wish to upgrade your subscription, please cancel your current subscription in your customer account and purchase a new subscription here.

License & Customer Account

I did not receive my license key!

After purchasing a license, your license key is sent to the email address you used to buy the license. In case you didn't receive the email containing the license key, please check your spam filter!


You can also access the license key in your  customer account. To log into your customer account, please use the credentials we've sent to you after registering with our service. In case you forgot your password, you can claim a new password here.


If you're still having trouble receiving your license key, please contact the MailJerry support.

Can I use my license on multiple devices?

All licenses can be used on a maximum of 2 devices at the same time.

How do I access my customer account?

You can access your customer account at


To log into your customer account, please use the credentials we've sent to you after registering with our service. In case you forgot your password, you can claim a new password here.

How can I cancel my subscription?

You can cancel your subscription at any time in the customer center. A cancellation is possible up to one day before the next renewal. If you deactivate your subscription in the customer center, your monthly or annual subscription will no longer be renewed in the future.

What are the cancellation periods for subscriptions?

You can cancel your subscription in the customer center up to one day before the next renewal. Once your subscription is deactivated, there are no further costs.

Money-back Guarantee

What is the money back guarantee?

The money-back guarantee allows you to test our paid services risk-free.


With this guarantee, you can rest assured that if you are not satisfied with our product, you will be refunded the amount paid.

How do I claim the money-back guarantee?

Please contact our support and tell us your license number or the e-mail address you gave when you made the purchase.

The refund will be processed within our service hours and the refund back to your means of payment will be initiated.

Our service team will contact you if we have any questions or if we cannot clearly assign your details to a transaction.

In which cases can I request my money back?

If you are not satisfied with our software, you can always make use of the money-back guarantee without giving a reason.


Of course, we look forward to your feedback so that we can improve our services in the future.

Do I have to justify why I want to claim my money back?

No. Of course, we would be very happy to receive your short feedback so that we can improve our software and our services.

Does the money-back guarantee apply to everyone?

Yes, the money-back guarantee applies to all paying customers.

Subscription holders can claim the money-back guarantee at any time for the current month (see below for the refund amount of monthly and annual subscriptions).

How much time do I have to claim my money back?

Any time for the current monthly period.

How much money will I get refunded?

For monthly subscriptions, the monthly fee for the current month will be refunded. Months already passed cannot be refunded.

For annual subscriptions: 100% in the first month after purchase, after that the refund is limited to the amount of the annual subscription divided by 12 (= amount for the current month).

How is the payment refunded?

After the refund has been processed by our service team, the respective amount will be refunded to the payment method used for payment (e.g. PayPal account, credit card).


Unfortunately, it is not possible to use a different means of payment than the one used for the initial payment.

What happens when I redeem a voucher?

If you redeemed a voucher code at the time of purchase, you can request a new voucher for the same amount.

I have a subscription. How does the money-back guarantee work in this case?

Contact our support and tell us your license number or the e-mail address used when purchasing.


For monthly subscriptions, we will refund the amount for the current month.


With annual subscriptions, you will receive 100% of the amount back in the first month from the date of purchase. Afterwards, the refund is limited to the amount of the annual subscription divided by 12 (= amount for the current month).


Once the money-back guarantee has been redeemed, your subscription will be automatically canceled and there will be no additional costs.

I have an annual subscription – how much money will I get back?

In the first month after purchase you will receive a 100% refund, after that the refund is limited to the amount of the annual subscription divided by 12 (= amount for the current month).

Will my subscription continue after I have claimed my money back?

No. If you claim your money back, we will assume that you are not satisfied with our product. Therefore, your subscription will be canceled automatically.

Are there any reasons the a refund can be denied?

In general, we do not refuse anyone to redeem the money-back guarantee.


However, we reserve the right to refuse the refund if the money-back guarantee is abused wilfully and/or in bad faith (e.g. after excessive use of the service, successful data migration, repeated requests for a refund...).


To date we have not refused anyone a money back claim and, given the honesty and fairness of our customers, we are convinced that this will not be necessary in the future either.

Privacy & Security

Do you have access to my emails?

No, we copy your emails in encrypted batches, with means that we have only access to your email header, but no email content.

Do you store my access data?

Yes, we store the access data to your email accounts for the duration of your email migration. We do need to store your credentials to be able to reconnect with your mailbox in case your email server closed the connection and for syncing your emails after the migration.


Of course, the access data is encrypted and only readable for our email migration service. Our support team is not able to retrieve your password or access your email accounts. Your access data is deleted as soon as your migration including syncs has finished or after you deleted the migration in the email migration tool.

Do you store my emails?

No, we do not access any of the text content of your emails and do not store any email data.

Do you store my payment information?

No, we do not store any payment information on our serves, payments are carried out via, which is a PCI-compliant merchant service provider. Of course, all communication between our servers and is encrypted.

How secure is my data?

We take great measures to ensure that your data is 100% secure and your privacy protected at all times:

  • Your email data is retrieved through a fully encrypted connection.

  • Our servers and databases are located in the EU and are managed by certified experts.

  • All communication between your mailserver and MailJerry is protected and encrypted.

  • None of your email data will be altered or changed, we only transfer your data between your mailboxes.

  • We cannot read your data and do not store your emails at any given point.

Didn’t find the answer you were looking for?

Our support team is at your disposal from Monday to Thursday from 09:00 a.m. to 06:00 p.m. (CET).