SysTools Office 365 Merge

Perfect Solution to Combine Two Office 365 Accounts / Tenants Mailbox Data.

(Average Rating 4.2 Based on 60 Reviews)

office 365 merger tool





  • Merge Two Office 365 Accounts of Same or Different Domains / Tenants
  • Join All O365 Items: Emails, Contacts, Calendars, Tasks, Documents
  • Provides Options to Combine Office 365 Tenants Shared Mailboxes
  • Allows to Combine Office 365 Tenants After a Merger or Acquisition
  • Function to Set a Priority of Accounts to Combine Them at Priority
  • Apply Date or Category Filters to Merge Exchange Online Mailboxes / Domains
  • Ensures that Data Integrity is Maintained All Over the Process
  • Mandatory to Have Valid Details of Exchange Online Mailboxes to be Combined
  • Feature to Directly Import CSV File for Adding Details of O365 Accounts
  • Does not Reveal or Store Credentials of the User's Office 365 Account
  • Compatible with Windows 10 (64-bit), Windows Server 2012 / 2016

Free Live Demo - SysTools Office 365 Merge Fully Secured Download Version


Expert Reviews


Why You Need to Combine Office 365 Tenants After a Merger or Acquisition?

combine Office 365 tenants

All the IT companies have their unique IT set up and services. So, when two or more customer companies merge or a parent company acquires a different organization, it is required that the entire archived data needs to be merged into a single tenant. Doing so consolidate the infrastructure, minimize the duplicacy, and enables to manage all the internal users using a single vendor. However, while combining two Office 365 tenants, the merger of dissimilar IT company encounters several complex challenges within mergers or acquisitions. Such as:

  • Microsoft does not allow to merge Office 365 tenants and mailboxes cannot be reassigned even if they exist in the same location.
  • A single custom domain cannot be used in two Office 365 tenants at a time as it needs to move the domain from first tenant prior adding it to another tenant.
  • Passwords cannot be merged of tenants for cloud-only users. If changing email addresses and Online Services ID while merging process then, credentials need to be updated on devices.
  • Temporary or permanent changes in username can change mailbox identities. This can be done easily but Outlook needs to be reconfigured in most of the cases.

How Office 365 Merge Tool will help you: Software is basically designed to overcome all such challenges and complications while combining two disparate Office 365 tenants. It will merge Office 365 users emails, contacts, calendars, documents.

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SysTools Office Tenant Merge Tool

Why This Tool to Combine Office 365 Tenants

What are the Constraints of Manual Office 365 Merging?

  • Using manual method, direct merge Office 365 tenants mailboxes is not possible.
  • Office 365 mailboxes need to be offloaded then, re-upload. It is a complex procedure.
  • Dependence on the on-premise infrastructure for storing and exporting the mailboxes is essential.
  • The manual solution does not provide coexistence and prevents from calendaring or mail routing.
  • Native tools impose various limitations and it is a time-taking process that is highly prone to errors.

What is the Best Solution to Merge Two Office 365 Tenants?

Office 365 Merge Tool is a powerful utility to merge two different Office 365 tenants in a seamless manner. The software comprises all the functionalities to overcome the shortcomings of manual solution. It allows merge Office 365 tenants mailbox and does not make any changes in Metadata Despite this, it includes multiple other handy features:

  • Combine two Office 365 emails, contacts, calendars, documents
  • Merge Shared Mailbox to Office 365 Tenants
  • Merge Office 365 tenants after merger or acquisition
  • Filters to merge Office 365 tenants mailboxes data
  • Auto-authenticate mailboxes to merge 2 Office 365 accounts
  • Import CSV to create a mapping between Office 365 source & destination accounts

Main Screen

Merge Office 365 Tenant, Domains, Accounts, Mailboxes

The Office 365 Merger allows to merge the mailboxes of Office 365 tenants/ domains. It is capable enough to combine various data items among multiple or same Office 365 tenants. The tool allows to merge Office 365:

Tenants: Tool will combine mailboxes of multiple Office 365 tenants, it also capable to merge users account mailboxes in the same tenant.

Domains: It can be used for combining mailbox data of two domains of different Office 365 tenants. In addition, The tool is capable enough to merge the mailbox data of two different domains of a single tenant.

Accounts: The Office 365 merge Tool combines multiple Office 365 users mailbox of different tenants. While merging office 365 accounts, the tool merges all the data items of two Office 365 tenants.

Shared Mailbox: Office 365 tenant merge tool, allows to combine shared mailboxes of different Office 365 tenants.

Features of Office 365 Merger Tool

Know Prominent Features of Tool with Detailed Description

Merge Office 365 accounts

A Tool to Join Two Office 365 Tenants

This utility is a direct and barrier-free way for combining multiple Exchange Online accounts in one profile. The software collectively merges/ federates all the O365 mailboxes, mentioned by the end user. It will map and unite folders of mentioned ids and password all-at-once.

Import CSV file

An Option to Add Details Through CSV File

Instead of mentioning the required tenants credentials one-by-one, users can save them in a single CSV file and then, just need to click on Import CSV button for browsing it. After that, software will automatically extract all details from the browsed file and load them on its panel.

Map Office 365 accounts

Map and Combine O365 Accounts

Office 365 Merge software will map user mailboxes to combine multiple Office 365 accounts. After a successful mapping procedure, it will be authenticating each item and proceed with the merging procedure. One will be able to continuously track this authentication process for their job accomplishment.

Maintain data integrity

Preserves Source and Integrated Data Items

Talking upon the perspective of data integrity, users need not to worry about it because this Office 365 Merger utility guarantees that no data will be altered while accomplishing combination procedure. The application provides a simplified way to merge existing Microsoft account to new 365 mailbox.

Filter Options

Filter Items Which are to be Merged in Office 365

The tool offers an ultimate feature of adding two accounts on basis of certain filtering criteria. Users can use date filtering option by specifying To-to-From date while performing joining procedure.

Generate Live Report

Generate Live Merging Procedure Report

It is now possible to track live status of combining mailboxes of Office 365 without PowerShell commands. Microsoft Office 365 tenant merger software displays live status of combining process with attributes like Source ID, Target ID, number of mails merged, Process progress, status, etc.

Merge Selective Items

Option to Merge Selective Items

The tool offers an ultimate feature of adding two accounts on basis of certain filtering criteria. Users can use date filtering option by specifying To-to-From date while performing joining procedure.

Add Multiple Projects for Merging

Add Multiple Projects for Merging

The tool allows us to add multiple Office 365 projects for merging, with this option users can combine multiple Office 365 tenants simultaneously. To perform multiple tenants merge operation users need a highly configured machine.

Office 365 Merge Utility – System Specifications

Free Download Software to Combine Office 365 Tenants Data on Windows OS

Software Download for Windows

Size: 91.0 MB

Version: 5.8.0

MD5: 4733f921888712a1b1bae237e25d3b81

Software Download for Linux

Size : 88.4 MB

Version : 5.5.0

MD5 : 121def6d992374101c96103b4ca5df4a

Trial Limitations

Free version of Office 365 Merge software will combine two users mailbox.

System Specifications

Hard Disk Space
500 MB of free hard disk space required

8 GB is recommended

Minimum of 2.2 GHZ


  • Destination User(s) should be already created at destination Admin account.
  • User Group(s) should be already created at destination account.
  • Valid Activation Code.
  • Register Application with Microsoft Azure Active Directory & Enable API Permission for Source & Destination Tenant as follows : Register Application with Azure AD
Source Tenant Destination Tenant
Mail.ReadWrite Mail.ReadWrite
full_access_as_app full_access_as_app
Microsoft Graph
Calendars.Read Calendars.ReadWrite
Contacts.Read Contacts.ReadWrite
Directory.Read.All Directory.ReadWrite.All
Files.Read.All Files.ReadWrite.All
Mail.Read Mail.ReadWrite
User.Read.All User.ReadWrite.All

Operating System

Windows 10 (32-bit & 64-bit), Windows 2012 / 2016 Server

For Linux: Ubuntu 18.04 LTS
Architecture: x86-64



Electronic Delivery


Office 365 Merger Order Now

DEMO and Licensed Version Comparison

Features DEMO Version FULL Version
Import CSV to Add Details
Apply Filters to Mailbox Items (Emails, Contacts, Calendars, Documents)
Authenticate & Merge Mailboxes
Generate Summary Report
Windows 10 & Previous Windows Version Supported
Combine Office 365 Accounts/Domains 2 User Mailbox
Merge Selective Mailbox Items 2 User Mailbox
Cost FREE $25
(5 Users)

Frequently Asked Questions

Commonly Asked Questions Regarding Office 365 Merge Tool & Their Answers

I want to know the working of this utility? Can you please explain?

merge Office 365 software

Get a Simple Guide to Join Microsoft 365 Accounts:

  • Step 1 - Install and Launch Office 365 Merge Tool
  • Step 2 - Select Items and Enter Office 365 Admin ID
  • Step 3 - Import CSV with Source & Destination Users
  • Step 4 - Select the Users & Validate Licensing
  • Step 5 - Click on Start Migration to Combine O365 Tenants

Yes, the user can unite/ join the mailboxes of 2 Office 365 domains using our Exchange Online mailbox merge utility.

Yes, you can accomplish the same task with help of following instructions:

  • Launch SysTools Office 365 merge application on your machine and then, go on with joining process of it.
  • When you find Select Categories section, you will have to check only the Contacts option.
  • At last, click on Start button for completion of merging process.
Yes, our Office 365 tenant merge software is totally a Windows-based application, which is compatible with all available versions of Windows 10 (64-bit), Windows Server 2012 and 2016.
There is no secretive storage database with us where your credentials are being stored by our product. We use user ID and password only for combining/ joining two email accounts of Office 365.
The time duration is totally dependent upon the amount of data to be merged. Apart from this, tool tries its best to accomplish the task within shortest period of time.
Yes, the emails of the source mailbox along with the destination mailbox can be viewed on the Outlook 365 of the destination mailbox after successful completion of the merging process.

What Customers Are Saying

Get What Users Say About Office 365 Tenants Merger Tool