In order to migrate emails from an existing Google/Gmail account to IONOS, some preliminary work is required. This article explains what is necessary.


A target mailbox has been created in IONOS Email (Basic/Business/Exchange).

Customise Gmail Security Settings

In order for the migration service to access your Google Account, you need a Google App password. This is a security code that is valid only for this purpose. Note that an app password can only be created with active 2-Step Verification.

  • Sign in to your Google Account.
  • In the top menu bar, click the circle icon with your profile photo or the first letter of your username.
  • Select Manage Google Account > Security.
  • If you haven't already done so, in the Sign in with Google data group, select the 2-Step Verification option. After successful activation, the App Passwords option will appear under Security .
  • Click on App passwords line and select Mail  as the app and whichever device that applies to you, e.g. Windows Computer.
  • Complete the setup by clicking Generate. The 16-digit app password is displayed.

You use this generated app password during the configuration of the migration service for the source mailbox (Google/Gmail mailbox).

Enable IMAP Access in Gmail

  • Sign in to your Google Account.
  • In the top menu bar, click the gear icon > See all settings.
  • Select the Forwarding & POP/IMAP tab.
  • Enable IMAP access. The status IMAP is enabledwill be displayed in green.
  • Complete your entry with Save Changes.

Validate Google Emails

Emails with the following criteria will not be migrated from your Google Account by default:

  • Attachment larger than 25 MB: To select these emails, type has:attachment larger:25M in the search box of your Google email account. Save the desired emails/attachments manually.
  • Emails without labels: To select these emails, type has:nouserlabels in the search field of your Google email account. To have these emails included in a migration, assign them a label. A folder with the same name will be created in the IONOS target mailbox during the migration.

Starting the Migration

After you have completed all the preparations in your Google Account, you can start the migration as described in the article Migrating Emails and Folders from an External Provider to IONOS.

Note that a migration may take longer for large Google mailboxes.