Chat now with support
Chat with Support

On Demand Migration for Email Current - User Guide

Introduction Preparing Migrations Test and Pilot Migrations Configuring and Running Migrations Post Migration Third Party Assessments and Certifications Glossary


  • Non-delivery reports migrated to exchange will not be as complete as if we they would be if they were sent from exchange based client. For instance, a non-delivery report migrated from IMAP server cannot be resent by opening it and selecting Resend in Outlook.
  • If an IMAP source has sent mail in a folder other than “sent items,” the target will have mail migrated to a folder of an identical name and not to the “sent items” folder in Exchange/Microsoft 365. The user can move the mail from one folder to another after migration.
  • The Follow Up flag is not migrated.

G Suite

IMPORTANT: It is not required to enable IMAP for migrations from G Suite on the organization level unless you need 'Important' and 'Starred' target folders to have the same non-English localized names as the corresponding Gmail labels on the source.

  • Tasks are not migrated.
  • Cannot currently migrate attachments on Google Events.
  • Currently, when migrating to Microsoft 365, Google Labels do not show up by default in the user's Categories list.

To have migrated Google Labels appear in the Microsoft 365 Categories list, in O365, open manage categories... from the categorize menu and select add new category. Then create a category that exactly matches a category that was applied to an O365 message during the migration. All messages marked with that category will take on the color applied (if any) and the category will remain on the user's list for future use.

This can also be achieved in Outlook 2010. From the Home tab, click the Categorize button and then select All Categories. You will see your labels that are missing with (Not in Master Category List) next to the name. Select the category, click New, select a color, and click Save.

  • In G Suite to Exchange/Microsoft 365 migrations, attachments that appeared normally on the source may show up on the target as a ‘winmail.dat’ file. These files are actually winmail.dat files on the source as well, but G Suite automatically interprets them as their original file type. To view them on the target, users will need to use a winmail.dat viewer.
  • The Chats label is no longer supported due to Google Chat was officially shut down (

  • Currently, if a G Suite user has "Make changes AND manage sharing" permissions on a secondary shared calendar, this shared calendar will be migrated, but no sharing connection is maintained between the two mailboxes, which means the shared calendar on the target will not be updated when the owner updates their own calendar. If this behavior is not desired, users need either to manually remove the shared calendars on the target after migration, or follow the steps below prior to migration to change the Sharing Permission Settings.

Note: ODME does not migrate primary shared calendars.

    If you want to allow the migration of secondary shared calendars, which will become independent (orphaned) calendars in the target:

    On an individual user basis:

    1. Log in to the account whose calendar is being shared.
    2. Go to Calendar > Settings (gear icon) > Settings > Calendars.
    3. Click on sharing for the desired calendar.
    4. Under "Share with specific people", change the Permission Settings for the user(s) to the "Make changes AND manage sharing" permission.
    5. Save.

    If you want to prevent the migration of secondary shared calendars, so that they can be setup natively as shared calendars in the target:

    On an individual user basis:

    1. Log in to the account whose calendar is being shared.
    2. Go to Calendar > Settings (gear icon) > Settings > Calendars.
    3. Click on sharing for the desired calendar.
    4. Under "Share with specific people", change the Permission Settings for the user(s) with the "Make changes AND manage sharing" permission to any other option you want.
    5. Save.
  • ODME does not migrate some Contact fields from G Suite to Microsoft 365.
    Fields that are currently supported:

    • Name
    • Job title, Company
    • Phone Numbers
    • Picture
    • Notes
    • Email Address
    • IM
    • Birthday
    • Relationship


      Note: When migrating contacts, ODME explicitly validates the Email Address property. If the property does not contain the correct e-mail address, it will not be migrated.

    Custom G Suite fields that cannot be migrated from G Suite to Microsoft 365:

    • Phonetic Last
    • Phonetic First
    • URL
    • Internet Call
    • Custom Fields
  • ODME does not migrate contacts that are shared from other G Suite users. For example, the user A shares some contacts with the user B. Theses shared contacts will not be migrated when you migrate the user B to the target, and they will not be automatically shared to the user B even if you migrate the user A to the target as well.


  • For Zimbra 8: ODME cannot migrate Zimbra contact group members which contain an email address only.
  • Migration of mailboxes from Zimbra 6 is not supported.
  • Shared and search folders are not migrated
  • Only the first IM address is migrated for each Zimbra contact. Additional IM addresses, if any, are not migrated.
  • The "other" URL for Zimbra contacts is not migrated.
  • Items contained Zimbra Briefcases are not migrated.
  • ODME does not correctly map contact File-As field "Company (First Last)".
  • Tags applied to mail, contacts, and tasks are not migrated.
  • Certain mail items that can be defined in the Zimbra Outlook connector are not supported in the Zimbra UI and as a result cannot be migrated. These mail items include, but are not limited to, the recurrence information for tasks and completed date fields.
  • ODME cannot migrate Zimbra item fields that do not exist on the target. For example, when migrating to O365, the location field on tasks will not migrate as there is no comparable field for tasks in O365.
  • ODME support migrating a total of 3 email addresses per contact to an Exchange target mailbox. Zimbra has fields for 5 addresses per contact.
  • ODME cannot migrate to an Exchange target group members in Zimbra that do not have contacts with defined email addresses. This is because Exchange requires each member of a distribution list to have an email address, while group members in Zimbra are not required to have an email address.
  • ODME does not migrate message tags.
  • ODME does not support migration of excluded dates in recurring meetings. For example, if a meeting is scheduled for "every Friday, except 2015-05-01", then it will be migrated as recurring “every Friday” - the excluded date will not be migrated to the target server.

Known Issues

For the list of known issues, please refer

Related Documents

The document was helpful.

Select Rating

I easily found the information I needed.

Select Rating