How to Migrate from Kerio to Office 365

• 14 January 2026
• Migration
• Written by Editorial Team

• Introduction
• Why Migrate from Kerio to Office 365?
• Why Office 365 is Better than Kerio?
• Prerequisites for Kerio to Office 365 Migration
• Manual Methods to Migrate Kerio Mail to Microsoft 365
• Steps for Migrating from Kerio Connect to Office 365
• Why Choose Apps4Rent for Kerio to Office 365 Migration?
• Kerio to Office 365 Migration FAQs

Are you looking for Kerio Connect to Office 365 migration? Though Kerio is a powerful, feature-rich email solution with attractive solutions for email, calendar, instant messaging, and collaboration, it isn’t suitable for all kinds of organizations. Kerio was specifically designed for small and mid-sized businesses looking for enterprise-class email solutions.

When it was launched in 2001, Kerio Connect became one of the earliest groupware solutions offering a fully featured enterprise email solution. While it has evolved considerably since then, Kerio still has some glaring drawbacks that prompt users, especially large organizations, to consider migrating to Microsoft Exchange or more precisely Office 365.

Why Migrate from Kerio to Office 365?

For the uninitiated, Kerio is specifically designed for small and medium businesses. When these businesses grow in size, their requirements evolve too. The email solutions that worked in the past would not be suitable in the present. A large business requires sophisticated enterprise-level features, with fairly good control over security and compliance. Though Kerio is a well-rounded enterprise-level email solution, it has some gnawing drawbacks that can be solved only with modern email solutions. The fact remains that Kerio is built around email as the primary means of collaboration despite having features such as instant messaging. Microsoft Office 365, on the other hand, is built around the cloud which bundles all productivity applications together including your emails, calendars, contacts, and more.

Notwithstanding the competition, Microsoft continues to be the market leader when it comes to cloud-based email solutions. As one of the first companies to offer products with multi-site redundancy, Microsoft has exploited its first-mover advantage to good effect. By the end of April 2019, Microsoft Office 365 had over 180 million users.

If you are using Outlook with Kerio, you might have a very sluggish experience. Understandably, Kerio does not integrate well with Outlook. The outlook is best experienced with Exchange, as both of them are Microsoft products and blend together productively. There are also groupware aspects that make Office 365 a more viable option than Kerio.

Why Office 365 Is Better Than Kerio?

With its massive user base, including its sizeable workforce, Microsoft not only manages to test its products including Office 365 much better than most of its competitors but also releases new versions regularly with features developed on novel technologies at regular intervals of time.

Then there is also an element of legacy and familiarity. As the majority of the systems around the globe use Microsoft products as their business suite, Office 365 offers the added advantage of integrating popular Office apps seamlessly. Office 365 comes with pre-included OneDrive for Business, SharePoint, Teams, Yammer, and Power BI which is included in the Office 365 subscription plan.

Nothing can beat Microsoft’s efforts when it comes to data security. Microsoft is known to protect the data of its users vehemently, and it meets almost all compliance requirements of your business. Office 365 comes with features like Advanced Threat Protection and Office 365 Cloud App Security, which is arguably the most comprehensive security suite for large enterprises. Combined with Exchange Management Shell, which allows admins to make low-level configuration changes and script bulk changes, is an ideal solution for all types of enterprises.

What Are the Prerequisites for Kerio to Office 365 Migration?

Kerio to Microsoft 365 migration involves several prerequisites to ensure a successful transition. Here are the key prerequisites to consider before initiating a migration:

• Conduct a comprehensive assessment of your existing Kerio environment, including user accounts, email data, calendars, contacts, and other relevant data.
• Perform a complete backup of your Kerio data, including emails, calendars, contacts, and other important information.
• Ensure that you have the necessary Office 365 licenses and subscriptions in place to accommodate all users who will be migrating from Kerio.
• Ensure that your organization’s internet connectivity is stable and has sufficient bandwidth to support the migration. A slow or unreliable internet connection can cause delays and disruptions.
• Ensure that you comply with any legal requirements and data protection regulations relevant to your organization during the migration.

Manual Methods to Migrate Kerio Mail to Microsoft 365

Exploring manual options helps many organizations understand how to migrate Kerio to Microsoft 365 before committing to full-service providers. These approaches work well for smaller setups but reveal gaps as data volumes grow. Let’s break down the primary manual technique and its real-world limits.

Using Kerio Outlook Connector

The Kerio Outlook Connector stands out as the simplest manual path for Kerio to Office 365 migrations. Download and install it directly from Kerio’s site to sync emails, calendars, contacts, and tasks between Outlook and your Kerio server. Once connected, export data in standard formats like EML for emails or vCard for contacts, then import straight into Outlook connected to Office 365. Admins map user accounts one by one through the Exchange Admin Center for accurate transfers. This method shines for quick tests or single-user moves when migrating from Kerio to Office 365.

Limitations of Manual Migration

Manual processes falter quickly with larger teams chasing the Kerio migration to Office 365. Here’s why they fall short:

• Constant Oversight Required: The Outlook Connector risks data mismatches on attachments or calendar invites during bulk Kerio to Office 365 migration.
• Time-Consuming Cycles: Export-import loops eat hours and throttle under Office 365 limits.
• Missing Advanced Features: Shared folders and permissions often get skipped entirely.
• Compliance Headaches: Post-migration cleanup creates snags and user frustration without automation.
• Scale Issues: Manual methods take too long and fail for large teams. Expert migration services and third-party tools handle big migrations reliably.
  

Steps for Migrating from Kerio Connect to Office 365

Once you have decided to move from Kerio Connect to Outlook (Microsoft Exchange), which comes with the Office 365 subscription, you need to explore the available options. This depends on the volume of data that is to be migrated. For IMAP-enabled Kerio setups, IMAP migration to Office 365 offers a straightforward path through the Exchange Admin Center. There are plenty of tools available for Kerio Connect migration to Office 365, but it can also be done without the use of tools. An expert Office 365 migration service provider like Apps4Rent can seamlessly migrate all the ins and outs of migration which would save you plenty of hassle. Apps4rent follows a methodical process to migrate all the Kerio mailboxes to Office 365.

The easiest way to migrate Kerio to Office 365 would be to use the Microsoft Exchange admin center. It must be noted that Kerio saves data as simple text files. It saves emails in the .eml format, contacts as vCard, and calendar items in the iCalendar format. All these items can be imported into Outlook. Apps4Rent can perform the complex Kerio to Office 365 migrations without breaking a sweat.

• We create new Office 365 accounts for each user who needs to be migrated and ensure that these accounts are properly configured and ready to receive email data.
• We associate each newly created Office 365 account with the corresponding Kerio Connect account. This mapping is essential to ensure that email data is migrated accurately and to the correct user.
• We use the Microsoft Exchange admin center to migrate Kerio Connect accounts to Office 365.
• Instead of migrating all users simultaneously, we conduct the migration in batches. This approach minimizes the risk of failure and ensures that technical issues can be identified and resolved more efficiently.
• Users are then requested to log in to their Office 365 accounts to confirm if their emails have been transferred.
• Once the users have been migrated, we take care of all the post-migration issues through constant coordination with your technical team.

Apps4Rent Can Help with Kerio to Office 365 Migration

Migrating from one email system to another is almost always a tricky affair with a relatively high probability of data corruption. The approach you use should depend on the scale and magnitude of migration. At the end of the day, it boils down to the cost-benefit analysis of purchasing a fully automated tool vs. the man-hours required to manually migrate data such as contacts and calendars.

As a Microsoft Solutions Partner, Apps4Rent can help you migrate from Kerio Connect to Office 365 and help you choose an approach that is best for your business. If you need any help in any kind of Office 365 migration, contact our Microsoft-certified experts, who are ready to have a quick call with you. Feel free to contact us now!

Kerio to Office 365 Migration FAQs

1. Can Kerio mailboxes be migrated to Office 365?

   Yes, Kerio mailboxes transfer fully to Office 365 via IMAP or Outlook Connector exports. Emails, folders, and settings move intact during the Kerio to Office 365 migration. Apps4Rent, in particular, is an expert at migrating from Kerio to Office 365 and can migrate large data volumes seamlessly.

2. Does Kerio provide a built-in Office 365 migration tool?

   No, Kerio lacks a native migration tool for Office 365. Use the Outlook Connector or manual exports to migrate data from Kerio to Office 365. Third-party services like Apps4Rent’s expert Office 365 migration services simplify the process.

3. Does Kerio use EML format for email migration?

   Yes, Kerio stores emails in EML format, perfect for bulk exports. They can be imported directly to Office 365 mailboxes.

4. Can Kerio data be imported into Outlook before migration?

   Absolutely, export Kerio EML/vCard/iCal files to Outlook first. Then sync Outlook with Office 365 for a hassle-free migration from Kerio to Office 365. Great for testing small batches.

5. Is there any downtime during Kerio to Office 365 migration?

   No downtime is required. Migrations can be run in batches during off-hours while users keep working.

6. Can selective users be migrated from Kerio?

   Yes, specific users or departments can be migrated via account mapping. This is perfect for phased rollouts after migrating from Kerio to Office 365.

7. How long does Kerio to Office 365 migration take?

   Small setups finish in 1-2 days; larger ones take 1 week. Data volume and throttling set the pace for your Kerio to Office 365 migration timeline.

8. Is Kerio to Office 365 migration secure?

   Yes, encrypted connections protect all data in transit. Compliance stays intact while migrating from Kerio to Office 365. Microsoft security handles the rest.

9. Can old Kerio emails be moved to the Exchange Online archive?

   Yes, historical emails can be routed directly to Exchange Online Archive post-migration. Auto-expanding storage handles unlimited growth.