添付ファイル付きのOLMファイルを一括で簡単に変換する方法

武志雄人
Published: October 22nd, 2025 • 6 Min Read

If you use the Outlook email program on your Mac and are considering migrating to another email platform, you’re probably facing a major hurdle: knowing how to bulk convert OLM files with attachments. In this blog, we’ll walk you through this lengthy manual process and also introduce a smarter software solution that will make this bulk conversion easy.

A relatable scene that sounds just like your scene!

Imagine this scenario! You have all your important business emails, client contact information, email attachments, etc. stored in Mac Outlook. But now your company is migrating to Microsoft Windows Outlook. Suddenly, all your OLM files, filled with your most important data, are locked and inaccessible! Many users find themselves in this exact situation, needing to access their old Mac Outlook email data using another device or another email client. Here are some common questions you may have.

Q1. How can I batch convert all OLM files including email attachments?
A: It’s easy with a professional tool that supports batch processing.

Q2. Is there an easy way to transfer Mac Outlook emails with attachments to Microsoft Windows Outlook?
A: Of course! With our advanced Mac OLM Converter, you can easily transfer emails with attachments to Microsoft Windows Outlook in just a few minutes.

Understanding OLM Files and Their Importance

OLM files are generated by Mac Outlook. This file stores all your email messages, calendar data, contact information, task entries, and more. However, these OLM files are not supported by other email platforms, such as Microsoft Windows Outlook, Gmail, and Thunderbird. Therefore, you need to find a way to batch convert OLM files with attachments and easily migrate your valuable email data to other platforms.

There are some surprising statistics

According to Statista (2024), over 62% of working professionals are likely to switch between multiple email platforms and devices to accommodate changing work requirements. These switches often cause compatibility issues, necessitating file conversions to ensure a smooth data migration.

Realistic scenarios

Consider the case of Daichi, a marketing manager at a Japanese company. He recently switched from a Mac to a Windows PC. His previous Mac’s Outlook contained over 15GB of email data, including emails and attachments in OLM file format. He tried to open these emails on his new Mac, but it didn’t work. He needed a tool to batch convert these OLM files, and he found an easy-to-use tool.

When you need to convert OLM files in batches

Check out some scenarios where you need to know how to batch convert OLM files with attachments:

When switching from Mac Outlook to Microsoft Windows Outlook or other email platforms.
When creating a company-wide email backup before migrating a system.
When accessing older archived emails stored in OLM files.
Share business communications with teammates who use different email platforms.
Recovering important email data from an old Mac machine.

It’s a long road of manuals!

Learn some manual methods to convert Mac Outlook files into an accessible format.

First manual method: Using IMAP settings

Next, you need to sync your Outlook account on your Mac with Gmail.
After that, you need to move the OLM emails to your Gmail folder.
You can now re-sync your Gmail with Microsoft Windows Outlook.

advantage:

This method is free and works without any additional tools.

Disadvantages:

For large amounts of data, this process can take a significant amount of time to complete.
Email attachments and folder structures may not be preserved.
Depends on the internet.
There is also a risk of data loss.

Second manual method: Use MS Outlook’s Import/Export feature

- First, you need to export Mac Outlook data as OLM.

You can then use an intermediary system to import it into a compatible format such as PST.

advantage:

This method is suitable for smaller mailboxes.

Disadvantages:

This process is complex to learn and requires manual effort.
Email attachments and metadata may become corrupted.
This process does not easily support batch conversion of OLM files.

Disadvantages of the manual method

These methods can be quite time consuming when dealing with large numbers of files.
This process can result in lost or corrupted email attachments.
These methods require technical expertise to implement.
These methods cannot guarantee complete data integrity.

Now you see a smarter solution!

If you want to easily convert Outlook files on Mac in bulk, try BitRecover OLM Converter Wizard . This professional tool can convert unlimited OLM files, including email attachments, to multiple file formats like PST, MBOX, EML, PDF, etc. This multifunctional tool also allows you to convert OLM to PST .

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Key features of this great tool

This software can convert unlimited OLM files in batch with high accuracy.
This tool preserves email attachments, folder hierarchy, and email formatting.
The software supports multiple export options (PST, MBOX, EML, PDF, etc.).
There is no file size limit, so you can use as many as you like.
The tool is fully compatible with all Mac and Windows versions of Outlook.

How does this great software actually work?

To batch convert OLM files easily, follow these simple software steps:

First, launch the software and upload the OLM file.
Next, select the email folders you need to convert.
Then select the output format (e.g. PDF, PST, MBOX).
Next, set the destination path for the converted files.
Finally, click “Convert” and the process will start automatically.

Do’s and Don’ts to Consider

What to do:

For accurate and easy results, rely on our certified solutions.

Please back up all your original OLM file data before starting the conversion.

What not to do:

If your mailbox is large or complex, do not use the manual method.

Do not interrupt the conversion process.

User queries and their answers

How to easily convert multiple OLM files attached to an email?

You can use a handy tool that will show you how to easily convert OLM files with attachments in bulk.

Can I convert OLM files to PST manually?

Yes! There are ways to convert them manually, but they’re quite difficult and involve the risk of losing attachments. That’s why we recommend using a third-party OLM file converter, which is easier.

Closing remarks

If you are migrating from Mac Outlook or want to back up your old Mac Outlook email data, you need to know how to batch convert OLM files with attachments. Doing it manually is difficult, risky, and time-consuming. Therefore, it’s better to make a wise decision and use a professional OLM file converter as an easier solution.