Easy Steps to Migrate Hosted Exchange to Office 365

Published On - November 28, 2025 by Nasir Khan | Reading Time: 5 minutes

Many organizations that have been using Hosted Exchange are now planning to move to Office 365 (Microsoft 365) because it offers better security, flexibility, and assurance. Hosted Exchange is usually not recommended by the organizations, as they have to store their Microsoft Exchange in a third-party cloud however it has some benefits.

If you’re also thinking about moving your Hosted Exchange data to Office 365/Microsoft 365 for any reason, this guide will help you understand everything—from migration reasons to migration methods and the step-by-step process.

An Overview of Hosted Exchange:

Hosted Exchange is a cloud-based version of Microsoft Exchange Server offered by third-party hosting providers. In simple words, your mailbox runs on an Exchange Server, but not on your premises. Users use it to mitigate the issue of managing hardware issues in their own premises.

Why Migrate Hosted Exchange to Office 365?

Users prefer Office 365 over Hosted Exchange because it is more secure, scalable, and fully managed by Microsoft. Some of them are explained here:

• Trust Over Microsoft’s Data Security: Office 365 offers stronger security features like MFA and encryption, which are more advanced compared to hosted Exchange providers. This helps keep your emails and data safer.
• Large Storage and Accessibility: Office 365 provides large mailbox storage (50 GB to unlimited with archiving) and allows smooth access from any device, anywhere. Moreover, you can take a plan as per the data storage needs.
• Better Collaboration Tools: Office 365 comes with Teams, SharePoint, Word, and OneDrive, offering stronger collaboration and communication features.
• Suitable Plans for All: Microsoft 365 comes with various plans that suit everyone’s needs. It offers plans for individuals and businesses, and end users can purchase the plans as per the need.

Available Methods for Hosted Exchange to Office 365 Migration

You can migrate from Hosted Exchange to Office 365 using manual migration methods or with a professional automated tool. Below, we have explained both options so you can choose the right one. However, large organizations/ professionals skip manual ways as they are not suitable for large-scale migrations.

Manual Methods:

1. Migration Using IMAP:

This method migrates emails from Hosted Exchange to Office 365 using IMAP.

Steps to follow:

1. Log in to the Hosted Exchange Admin Center.
2. Enable IMAP for user mailboxes.
3. Export the user list to a CSV file.
4. Log in to Microsoft 365 Admin Center.
5. Go to Setup → Data Migration → IMAP.
6. Upload the CSV file with mailbox information.
7. Select the mailboxes and start the migration.

2. PST Export and Import

You can export mailbox data to PST files using Outlook and then import them into Office 365.

1. Open Outlook and configure the Hosted Exchange mailbox.
2. Go to File → Open & Export → Import/Export.
3. Choose Export to a file → Outlook Data File (.pst).
4. Save the PST file to your system.
5. Create an Office 365 profile in Outlook.
6. Import the PST file into Office 365 mailbox.

Moreover, you can also try the Network Upload Method but it is very lengthy and uncertain.

Limitations and Drawbacks of Manual Methods:

• Very time-consuming and requires technical knowledge.
• PST files may get corrupted during export or import.
• Cannot migrate contacts, calendars, or large mailboxes smoothly.
• High chances of data loss or structure loss.
• Not suitable if you have large mailboxes and you are willing to migrate mailboxes of an organization from Hosted to Office 365.

Professional Solution—Regain Hosted Exchange to Office 365 Migration Tool

Professionals always prefer a user-centric utility for a fast, accurate, and secure migration. The Regain Hosted Exchange to Office 365 Migration Tool is a preferred choice of the users. It allows full mailbox migration without losing structure, attachments, formatting, or metadata.

Free Download100% Secure Buy NowPrice: $89

Steps to Migrate Using the Professional Exchange to Office 365 Migrator:

1. Download and launch the Regain Exchange Backup and Migration Tool.
2. Log in using Hosted Exchange credentials.
3. The tool will automatically detect all mailboxes.
4. Select the mailboxes or folders you want to migrate.
5. Choose Office 365 as the destination by clicking on the Cloud Migration button.
6. Enter your Office 365 admin credentials (Supports both basic and MFA).
7. Click Start Migration.

Some Key Features Offered by Regain Hosted Exchange to Office 365 Migration Tool:

• No mailbox size limitations during migration. It also works for On-Premises Exchange to Office 365 Migration.
• You can also save Exchange mailboxes into PST, MBOX, EML, EMLX, PDF and MSG file formats.
• It also facilitates migrating from any version of Exchange Server to another.
• Import Exchange mailbox to Office 365, Gmail, Yahoo Mail, AOL Mail, Hotmail, Godaddy, Hostgator, Thunderbird and Google Workspace
• Transfers emails, contacts, calendars, tasks, and attachments.
• Regain Hosted Exchange to Office 365 Migration tool maintains folder hierarchy and metadata.
• This utility provides the option to migrate multiple mailboxes at once.
• It is compatible with all versions of Windows OS.
• There is a free demo version available to check the performance.

Conclusion:

Migrating from Hosted Exchange to Office 365 becomes essential for enhanced security, high uptime, and better collaboration tools. While manual migration methods exist, they come with limitations and data loss risks. To ensure a smooth, accurate, and secure migration, using an automated Regain Hosted Exchange to Office 365 Migration Tool is the most reliable choice. A free demo version and free 24*7 technical support is always available with Regain’s utilities.

Frequently Asked Questions:

Q1. Can I manually migrate from Hosted Exchange to Office 365?

A. Yes, you can export mailboxes to PST or use IMAP, but these methods are time-consuming, and you may lose important data.

Q2. Will my contacts and calendar also migrate?

A. Absolutely, with the help of the Regain Hosted Exchange to Office 365 Migration tool, users can also transfer contacts and calendars.

Q3. Does the tool provide a preview of emails before migration?

A. Yes, the tool offers a detailed preview of emails, attachments, contacts, calendars, and other mailbox items before migration or backup.

Q4. Are there any data size limitations, as I have to migrate large mailboxes from Hosted to Exchange Online?
A. No, there are no such restrictions with Regain’s tool. With the Regain Exchange Server Backup and Migration Tool, you get the freedom to migrate large mailboxes.

Q5. Can I back up my Hosted Exchange mailbox to PST format?
A. Yes, the software allows you to export and back up your mailboxes into PST format without losing metadata or folder structure. Moreover, you can also manage the resultant PST file size.