On-Premise to Exchange Online Migration – Detailed Explanation

Anuraag Singh | Last Modified: May 22nd, 2020 | MS Exchange, Office 365

Want to migrate On-Premise Exchange to Exchange Online? Are you facing difficulties in finding the procedure for switching your Exchange Server mailboxes? Well, you are searching at the right place. But first take a look at the takeaway through this informative blog.

Via this article you will be able to review the most effective method and practice which will be beneficial for the desired mailbox migration result. Also, it will somewhere help you in deciding the best option as per your organization needs to migrate On-Premise Mailboxes into Exchange Online.

Topics Covered in the Post

Generally, there are two methods for On-Premise mailbox into Exchange Online migration procedure. One is by migrating the mailboxes to PST and then import files to Office 365. This approach is recommended when you have a smaller number of user mailboxes. Second one is highly preferred for large organizations, having large number of user mailboxes, by On-Premise Server to Exchange Online directly.

When we talk about cloud-based emailing platform, it is hard not to talk about Microsoft’s Office 365. They started providing this technology in June 2011 and ever since there is no looking back. Since then, many leading organizations, which used to work on-premises emails, feel the need to switch into new cloud-based tech. Migrating these on-premises mail requires a skill set and ample of time, then how come these organizations decided to take this leap? Was there any actual benefit attached to it? Or it was just a same thing? Let discuss this!

Why You Need to Migrate On-Premise Exchange to Exchange Online?

Organizations which are using Exchange setup on their premises, states that it is because of the primary reason of gaining the universal access of the hardware and the ability to control entire Exchange data. But, this on-premises setup can also be responsible for disasters, putting significant data at risk. Moreover, in some cases, the cost of maintaining these servers can be challenging and a bigger task is of providing availability of server with 100% efficiency.

This is where migrating On-Premise Exchange to Exchange Online offers more significant advantages than on-premises setup.

  • Office 365 provides a complete scalable service. Which means the user is only asked to purchase more new user accounts, and the entire procedure of buying storage and additional hardware setups or even their configuration is completely eliminated.
  • It offers cost-effective services. Office 365 only asks to invest in Office 365 subscription and provides you all the features in its package. There is no need for maintaining any on-premises setup or anything else anymore.
  • Microsoft takes full responsibility for your data security. User does not have to worry about the loss of data due to any disaster, technical faults or even data theft anymore. The Microsoft experts understand the importance of the user’s crucial data.
  • Office 365 offers automatic upgradation of the latest software versions via a very seamless technique. The user does not have to go through many troublesome situations like server downtime or constant worry of software updates etc. anymore. Everything is taken care of automatically.

Issues Faced While Migration On-Premise Mailbox to Exchange Online

As we have noted, migration of On-Premise data is very risky and requires expert supervision and attention to be successful. Many things may not work. So please give it a try only if you are sure what and how to do it. Otherwise, you may face one of the following problems

  • On-Premise Exchange downtime during migration process
  • Stability Issues in the current Exchange Server
  • Slow Network Connections resulting in time wastage
  • Incorrectly configured CAS server, firewalls and proxy devices
  • Various security guidelines and policies of organization hampering the migration process
  • Users running the older version of Microsoft Outlook
  • Policy Compliance Issues

All the aforementioned issues are a small part of On-Premise Exchange to Exchange Online migration. Completing the entire task successfully without any error that too in one go looks like an impossible task looking at its complications. It requires proper planning, execution, expertise, in-depth knowledge and a lot of patience.

Perfect Option to Migrate On-Premise Exchange to Exchange Online

If you are looking to carry out the migration process in a smooth way and don’t want any complexities during the task, then you must consider using Exchange 2013 to Office 365 Migration Tool. This is a reliable and secure application to make the entire process quick and hassle-free. Users can easily export emails, calendars, and contacts to the destination account without losing any bit of data.

It offers a wide range of products such as the tool makes sure that the data integrity is maintained throughout the process. Moreover, the folder structure of the source mailbox is kept intact, and users get the folders in the same order in the destination account. Let us have a look at some of its unique set of features:

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  • Complete On-Premise Exchange to Exchange Online Migration
  • Software does not Impose any Mailbox Size Limitation
  • Option to Maintain Original Folder Structure at Destination Account
  • You can Prioritize Mailbox Migration According to Requirements

Step by Step Exchange On-Premise to Exchange Online Migration

1. Install & Launch On-Premise Exchange to Exchange Online Migrator

2. Select Exchange & Office 365 as Source and Destination Platforms

3. Enter Admin Credentials and Map Users of Source & Destination Accounts

4. Click in Start Migration button to Initiate Migration Process

Manual Solutions to Migrate On-Premise Mailbox to Exchange Online

There are several ways using which users can move their On-Premise Exchange mailboxes. All these procedures have their own limitations and some conditions under which they are useful. Users can choose any of these methods which best fits their requirements.

1. Migrate Mailboxes Directly into Exchange Online

  • Staged Migration – This method is useful in scenarios where the organization wants to migrate more than 2000 mailboxes at once. However, this process is only supported in Exchange 2003, 2007. To know more about the process, Click Here.
  • Cutover Migration – If the organization is looking forward to migrating upto 2000 mailboxes, then they can consider cutover migration. This solution can be implemented on Microsoft Exchange 2016, 2013, 2010, 2007, 2003. Click Here to know more.
  • Hybrid Migration – This procedure is best suited if the organization is having 150-2000 mailboxes and they want to move them over a period of time. It can be implemented on Exchange 2010, 2013 and 2016. To know more, Click Here.

2. Migrate On-Premise Exchange Server to Exchange Online via PST

Users can also export their crucial data with the help of Outlook PST file. If users are using Exchange 2007 or earlier versions, then they can use ExMerge utility or export-mailbox command to export On-Premise Exchange to Exchange Online. However, if the users have Exchange 2010 or later versions, then they can take help of new-mailboxexportrequest PowerShell command for the same to import Outlook data file to Office 365.

Limitations Associated with Manual Methods

  1. The manual procedures to export On-Premise mailbox into Exchange Online are too lengthy and complex.
  2. These methods require a lot of technical knowledge and larger downtime.
  3. There are situations when users can’t find their important data in the destination account as it might get lost during the process.
  4. Every method is version dependent and you must select the method depending on the number of mailboxes that you want to export.


On-Premise Exchange to Exchange Online migration process is such a crucial task for an organization and must be carried out in a proper way. Any type data loss or migration issue can create a lot of problem and cost a lot for the organization. Thus, in this article, we have mentioned all the issues and solutions using which users can carry out the process without losing any data. Users are recommended to go for the third-party application to make the task in a smooth way.