Understand Exchange Online data migration reports

Supported editions for this feature: Business Starter, Business Standard, and Business Plus; Enterprise Standard and Enterprise Plus; Education Fundamentals, Education Standard, and Education Plus; Essentials Starter, Essentials, Enterprise Essentials, and Enterprise Essentials Plus; Nonprofits; G Suite Basic and G Suite Business. Compare your edition

You can get detailed information on the data in your Microsoft Exchange Online migration.

You can review:

  • Email data
  • Calendar data
  • Contact data

User summary report fields & descriptions

Report field Description
Source user Email address of the user on the source account
Target user Email address of the user on the target account
Status Status of the user's migration:
  • Running—Migration is in progress.
  • Failed—Migration didn't complete because of discovery issues. To troubleshoot, check the migration report for the specified error.
  • Completed—Migration completed successfully. Any messages or labels that didn't migrate are listed in the migration error report.
Note: This report does not have a Skipped status because users are never skipped.
Emails migrated successfully Number of messages migrated successfully for the user (including messages that were skipped in an earlier migration)
Emails failed Number of messages that failed to migrate for the user
Calendars migrated successfully Number of calendars successfully migrated for the user (including additional calendars)
Calendars failed Number of calendars that failed to migrate for the user
Calendar events migrated successfully Number of events successfully migrated for the user
Calendar events failed Number of events that failed to migrate for the user
Contacts migrated successfully Number of contacts successfully migrated for the user
Contacts failed Number of contacts that failed to migrate for the user
Discovery failures Total number of:
  • Folders whose messages and associated subfolders were not discovered, either partially or fully
  • Calendars whose events were not discovered, either partially or fully
  • Contact folders with contacts and subfolders that were not discovered, either partially or fully
  • Root-level contacts that were not discovered (This failure is only counted once, even if it affects multiple contacts at the root level.)
Status details If the user's account is discovered, the status is OK. For accounts that are not discovered, you get the Failed to discover emails or calendars for the user. For details, check the migration report error message.

Migration report fields & descriptions

Report field Description
Status The migration status of the item:
  • Success—The item migrated.
  • Warning—The item migrated, but failed to complete as expected (for example, when an email migrates without the label associated with it).
  • Error—The item didn't migrate due to an error. Learn more about how to resolve common error messages.
  • Skipped—The item was skipped. Items can be skipped for the following reasons:
    • The item was migrated in a previous migration and wasn't updated in the source account before a delta migration.
    • The item was migrated to one user, then later migrated to a different user in the same migration wave (the migration wasn't exited and re-established).
Error/warning code & description The code and message associated with the error or warning status. Learn more about how to resolve common error messages.
Processing start time

Processing end time

 The migration start and end time for the item
Source type & source identifier
  • Exchange Online Email Folder Crawler: mailboxes/user_email/folders/folder_id
  • Exchange Online Email Folder: mailboxes/user_email/folders/folder_id
  • Exchange Online Email Message Crawler: mailboxes/user_email/folders/folder_id
  • Exchange Online Email Message: mailboxes/user_email/messages/message_id
  • Exchange Online Calendar Crawler: users/{user}
  • Exchange Online Calendar: users/{user}/calendars/{calendar}
  • Exchange Online Event Crawler: users/{user}/calendars/{calendar}
  • Exchange Online Event: users/{user}/calendars/{calendar}/events/{event}
  • Exchange Online Contact Folder Crawler: users/{user}/contactFolders/folder_id
  • Exchange Online Contact Folder: users/{user}/contactFolders/folder_id
  • Exchange Online Contact Crawler: users/{user}/contactFolders/folder_id
  • Exchange Online Contact:
    users/{user}/contacts/contact_id
  • Exchange Online Contact Category: users/{user}/contact/{contact_id}/categories/category_id
Target type & target identifier
  • Gmail message:
    users/user_email/messages/message_id
  • Gmail label:
    users/user_email/labels/label_id
  • Calendar:
    users/{user}/calendars/{calendar}
  • Calendar event: users/{user}/calendars/{calendar}/events/{event}
  • Google Contact Group:
    users/{user}/contactGroups/contact_group_id
  • Google Contact:
    users/{user}/contacts/contact_id

Resolve common error messages

Error message Description & troubleshooting help
The connection is invalid. Please disconnect and reconnect then try again. The connection is invalid. Disconnect the connection and create a new connection. Then run the migration again.
Temporary error occurred A transient error. Run a delta migration.
User not found A user in the migration map wasn't found. Try the following steps:
  • Confirm the email addresses in the CSV file you uploaded in Select users to migrate are correct. Then, update any incorrect email addresses in the file and try uploading it again.
  • Export the User Report and check the source and target users are correct.
  • In the migration settings, make sure you chose to copy user addresses that aren't found in the list you uploaded.
The source email address is invalid The user is not present in the source account. Add the user to the source account, and run a delta migration.
Virus or other attachment problem Gmail blocks messages that might spread viruses, such as messages that include executable files or certain links.

For more information, go to File types blocked in Gmail.
Connection not in usable state Your connection contains errors and is no longer in a usable state.

Disconnect and create a new connection. For details, go to Connect to your Microsoft account.
All required OAuth scopes have not been granted access Some or all of the required OAuth scopes haven't been granted domain-wide delegation.

Disconnect and create a new connection. For details, go to Connect to your Microsoft account.
Error occurred while generating user credential Domain-wide delegation hasn't been granted. In most cases, the domain-wide delegation process completes within a few hours, but you should allow up to 24 hours.

When the process is complete, run a delta migration to retry the failed tasks.
Found entries missing in the identity mapping for <username> A source user that was not mapped to a target user in the identity map was discovered during the migration.
  1. Remove the identity map.
  2. Correct the source user mapping.
  3. Upload the corrected map.
For details, go to Select users to migrate.
Invalid user provided in migration mapping A user email ID in the migration map is invalid or is not a Google email ID.
  1. Remove the migration map.
  2. Correct the source user mapping.
  3. Upload the corrected map.
For details, go to Select users to migrate.
User provided in migration mapping does not belong to a Workspace customer A target user email in the migration map is not a Google Workspace email.
  1. Remove the migration map.
  2. Correct the target user mapping.
  3. Upload the corrected map.
For details, go to Select users to migrate.
Label name exists or conflicts with label A label on the source account already exists on the target account. Remove the label from the target account and run a delta migration.
Mail service not enabled Turn on the Gmail service for your users. For details, go to Turn Gmail on or off for users in your organization.

If the error persists, wait for a few hours and try the migration again.
Unable to fetch resources for crawling source mailbox

Failed to crawl the source mailbox

Failed to authenticate with the source mailbox

Deadline hit while crawling the source mailbox

Source mailbox quota has exceeded

 These are temporary issues. Wait a few hours then run a delta migration.
The source mailbox concurrency limit has been exceeded Users should avoid using their mailboxes while a migration is running. Run a delta migration to fix this issue.
Certain draft emails can fail due to missing 'From' header. Please check the headers of the draft emails and try running a delta migration. Draft email messages in Outlook must have exactly one email address in the From field or they will trigger this error.
  1. Ensure your draft email messages have one address in the From field.
  2. Run a delta migration.
Google Calendar Service is disabled for the target user. Please check the user's Google Calendar settings and try again. Turn on the Calendar service for your users. For details, go to Turn Calendar on or off for users.
The event has been modified in the target calendar. If you want to bring a new copy of the event, please delete the event in the target calendar and try again. After the migration, if the event has been modified in Google Calendar, then it cannot be migrated again (either in a full migration or delta migration).

To migrate the event again, delete the corresponding event in Google Calendar and rerun the migration.
Google Calendar needs the user to be either the organizer or an attendee of the event. Please check the event and try again. If the user is not an attendee or the organizer of the event, the event migration will fail.
Unsupported recurrence pattern in Google Calendar. The recurrence pattern for the recurring event is not supported by Google Calendar.
Calendar quota has exceeded. Please try again later.

Unable to fetch resources for writing to target calendar. Please try running a delta migration.

Source user fetch failed for attendees: <username1>,<username2>

Source user fetch failed for organizer: <username1>

 This is a temporary issue. Wait for a few hours and then run a delta migration.
Access is denied. Check credentials and try again. If you receive this message during a data migration:
  1. Disconnect and reconnect your Exchange Online account.
  2. Run a delta migration.


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