Guide to Migrate Old Emails to Office 365 Step by Step
IT administrators worldwide will acknowledge the fact that there is no easy way to migrate old emails to Office 365 manually. You can’t hit an export button and magically expect all legacy mailboxes to appear inside the M365 cloud.
Despite the complexity of the process, there is no shortage of advice on quick workarounds. Most of which are outdated or only work in niche conditions. You can’t move confidential corporate email data to O365 via drag-and-drop without risking compliance violations.
However, continuing to use aging infrastructure is not a good alternative either. With AI democratizing cyberattacks, it’s now more important than ever to use a service that protects your data.
So to help my fellow IT admins, I have devised a series of methodologies, including manual and automated ones. This is done to showcase where exactly the manual method fails and how the right tool executes a flawless transition without corrupting your data.
Let’s start directly by discussing the risks of handling legacy email manually.
Why You Should Not Migrate Old Emails to Office 365 Manually
The legacy email platforms were meant to retrieve emails in small quantities over time. So if you try to throttle it for transferring tons of emails all at once, you run a risk of data corruption or server shutdown, even if you are just trying to migrate Outlook emails to Office 365 mailboxes.
It’s not the data but the server architecture itself that becomes the biggest bottleneck. Admins have to devise tactics to push against the friction. Here is the list of the most common problems you will see in a self-managed transfer.
- Folder structure flattens: The way users organize email data inside their account is important not only from a structure point of view, but also keeps them more productive. So if, after migration, this folder structure disappears, it could be very hard for users to reorder the data on their own. This is a common problem with autoforwarding and drag-and-drop type migrations.
- Metadata does not migrate: Sometimes the email messages remain as is but the data that informs when the messages came and who sent it at what time is completely erased. This can have serious consequences, whether you are trying to export Evolution mail to Office 365 or executing a massive, organization-wide Gmail to Office 365 migration.
- Timeout errors with downtime: If the migration methodology is too slow, it would cause downtime for users. Not only do admins run the risk of migration stopping midway without completing.
All these errors help us determine what exactly is needed in a solution.
What Does It Mean by Professionally Migrating Legacy Mailboxes to M365
To securely migrate old emails to Office 365, your strategy must be air-tight. Scripts and manual methods won’t suffice. So before you choose your solution, see that it has these core capabilities built in.
- 1:1 Replication: The data should mirror exactly as it was in the original; all emails, their metadata, and attachments must transfer completely. Moreover, the process should also keep account of the original folder structure and replicate it fully in the O365 environment.
- Concurrent Processing: Shifting one object at a time is too slow. So the method you select should be able to move multiple accounts in parallel without slowing down the data throughput.
- Delta Passes: Despite best efforts, there are chances that the source environment receives new messages after the migration has already begun. The method should have an option to be able to bring in this data too, without creating duplicates.
Ideal Solution for IT Admins
Stop relying on methods that can corrupt your data. To move enterprise information, you need a professional tool that every IT admin trusts. So, choose SysTools IMAP to Office 365 Migration Tool for moving old emails to the M365 cloud.
It shifts all emails while keeping the folder structure intact. Built-in filtering means you are in complete control. Test out the free demo today on any Windows 10, 11, or Windows Server 2016 and later. Check out these steps to use the tool:
- Step 1. Install a copy on your machine and select IMAP as the source and Microsoft 365 as the destination. Choose the email workload and apply the date filter if need be.
- Step 2. Then, in the source screen, choose the source platform and validate it.
- Step 3. In the destination screen, add the Office 365 details, validate them, and press Next.
- Step 4. Map the users with the help of the CSV template.
- Step 5. Select users, prioritize, validate, and start the transfer.
Conclusion
Now you know exactly how to migrate old emails to Office 365. The method you choose will determine whether or not you face data loss or admin tickets. Manual methods take up a lot of time and are not ideal for moving data at the enterprise level. So use a utility that can take care of all the heavy lifting for you.
Frequently Asked Questions
Q: How much time will it take to migrate all of my organization’s old emails to Office 365?
That depends entirely on how much data is in your source. The more data, the longer it will take. However, you can cut down on total migration time significantly by just switching from a manual method to the automated utility.
Q: Is there a total volume limit on the emails migrated to Office 365?
The only limit is the amount of space inside the O365 account. A regular account has a 50 GB or 100 GB cap, depending on whether you have Exchange Online Plan 1 or Plan 2, which can later expand to 1.5 TB for users on Plan 2.
Q: What happens if new messages arrive in my old email account when I have already started moving them to the cloud?
If you use the tool, it has a delta capture facility that will intelligently distinguish between the already moved data and the newly arrived data. Then, only move the newly arrived one.
