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At some point, every growing organization plans to migrate their data from Exchange Server to Exchange Online since a cloud environment is more attractive due to its cost savings, flexibility, accessibility, and security factors. While migrating data from one platform to another, there is always a risk of data loss. So is the case with Exchange Online when migrating from on-premises Exchange, Google Workspace, Public Folders, or any other IMAP server.

Data loss can become a nightmare for any organization since it results in downtime, shortage of resources, delays, budget rise, and breach of security. It is safe to say that nobody wants to go through all this trouble. There are ways to track and prevent migration data loss in Exchange Online, which we will discuss at length in this article.

What is Data Consistency Score, and how to view its status?

Many discrepancies are bound to occur during data transfer between different platforms. Any inconsistency arising during migration between a source and Exchange Online (destination) is used to determine the Data Consistency Score. This score is an identifier to check if the migration was a success or if any rectification is required. A range of factors is taken into consideration to determine the grade.

These are the four outcomes of the Data Consistency Score-

Grade Perfect Good Investigate Poor
Details This is an exceptional outcome of migration, where no inconsistency was observed. This is a decent outcome involving only one inconsistency, like metadata or folder permission went missing, which will not impact the data. In this grade, a small amount of loss is detected, resulting from frequent inconsistency types. A significant data loss has been identified and can leave an immense impact.
Further actions No approval needed No approval needed Skipped items require approval Skipped items require approval. Also, immediately contact Microsoft Support for further assistance.

You can view the Data Consistency Score at a per-user and per-batch level using these steps-

  1. Open Microsoft 365 Admin Center and click on Show all.
  2. Under Admin centers options, select Exchange.Admin centers options
  3. From the left panel, click on Classic Exchange admin center.Classic Exchange admin center
  4. Click on recipients and select migration. Here, you can check the status of all the batches put on migration migration
How to tackle Investigate or Poor grades?

The migrations from Google Workspace and Public Folder with an Investigate or Poor grade require approval for skipped items. You can manually handle the approval for Investigate graders. In addition, you can also use the Exchange Online Shell command to approve a user or batch-

Set-MigrationUser -ApproveSkippedItem
Set-MigrationBatch -ApproveSkippedItems

Perfect, Good, or Investigate graded batches can efficiently complete their migration process. However, you will be unable to complete a Poor migration outcome forcefully. You will have to contact Microsoft Support for any further assistance.

How to include the skipped items during a migration?

In the Classic Exchange admin center, you can check if all the items that are still not migrated using these steps-

  1. Click on recipients and select the migration tab.
  2. Select the batch which you would investigate. Click on View details in the information pane.
  3. From the entire list of users, select the one with the issue. Click on Skipped item details present in the information pane.

Once the user is detected, you can also use the following Exchange Online PowerShell command to include all the skipped items-

$userStats = Get-MigrationUserStatistics -Identify <user email address> -IncludeSkippedItems
$userStats.SkippedItems | ft -a Subject, Sender, DataSent, ScoringClassifications
What are the preventive steps to avoid data loss during migration?

These are a few data loss prevention techniques that you must keep in mind to eliminate data loss during migrating to Exchange Online:

  • Categorize your data
    There is no need to rush the migration of all the data in one go. You can skip the migration of no longer needed or outdated data. The first step must be understanding and categorizing all the data, from most to least significant.
  • Correct mapping of the data
    The transfer of information between two completely different platforms is an intricate procedure. With a small loophole, all your valuable data can leak. Mapping the data refers to providing a clear path from the source to the correct destination where the data will move.
  • Understand the destination platform
    You have to be aware of all the nitty-gritty of the destination platform. You must clearly understand Exchange Online protection and securities features in this case.
  • Communication with the staff
    While planning your Exchange Online migration, do keep in mind to plan the entire communication strategy as well. It will help to ease the process for all the staff. They will know what to do and whom to contact in emergencies.
  • No interruption during migration
    Ensure that there are no system or network issues during the entire migration that can halt or delay the process.
  • Find the right software
    Many users often are not sure about the right migration software. Kernel Migrator for Exchange is a professional Exchange Migration utility that promises an error-free migration between all kinds of Exchange environments. It offers pre-migration analysis and post-migration reports, which enable users to know the data which have been migrated successfully. Another feather in the cap is that you can continue accessing your mailboxes while the migration continues.


When organizations manually migrate Exchange to Office 365 (Exchange Online), a risk of data loss is always involved. This is made clear by the Data Consistency Score, which allocates grades to the migration- Perfect, Good, Average, or Poor. After the Poor migration grade, one should at once contact Migration Support. You can approve and then include all the skipped items for the rest of the grades. The entire migration procedure is complex, but you can perform a hassle-free migration if you use automated software designed for Exchange migrations. In addition, be mindful of all the preventive measures that should be practiced during the migration process.

Kernel Migrator for Exchange