An Honest Review of Top OLM to MSG Converter Software: Is GainTools Worth It?
By kensleyboyle 25-09-2026 4
Summary
Converting OLM files into MSG format is handy when you need to move email data from Outlook for Mac to an Outlook environment on Windows. However, working with large OLM files, folders, attachments and email properties manually can be cumbersome. This is where a dedicated OLM to MSG converter software can simplify the migration process.
In this review, we’ll dive deeper into GainTools OLM to MSG Converter to understand its features, conversion process, compatibility, pricing, limitations and overall usability. The goal is to provide a real and practical overview for users who are looking for an OLM to MSG converter in 2026.
What Is OLM to MSG Converter?
GainTools OLM to MSG Converter is a windows application that allows you to export emails from Mac Outlook OLM files to MSG. You can then open the resulting MSG files in Outlook for Windows.
The software does not need Microsoft Outlook to be installed to be able to convert. It also allows the user to retain folders/subfolders, live preview, filtration, attachment conversion, retention of email attributes and rich-text formatting.
This software is most beneficial for users who have an OLM archive created by Outlook for Mac, but need individual emails in the MSG format used by Windows Outlook.
Why Should We Convert OLM to MSG?
OLM and MSG are related to different Outlook environments.
OLM file is used mostly by Outlook for Mac whereas MSG is used to save individual Outlook email messages on Windows.
Users may require OLM to MSG conversion when they want to:
- Read Mac Outlook emails on Windows
- Save a single email as an MSG file
- Save attachments from email
- Move selected messages, not a whole mailbox
- Organize folders in a neat manner
- Open Converted Messages in Outlook Windows
- Preserve email formatting and properties
This process can be easier with a dedicated converter than trying to do it manually.
Core Features of OLM to MSG Converter
1. Conversion of OLM to MSG
The major functionality of the software is to convert Mac Outlook OLM emails to MSG format. GainTools especially offers the utility that helps to export Mac Outlook emails and attachments to MSG.
2. Preserve folders and subfolders
Perhaps you want to retain the original mailbox folder structure throughout the migration. GainTools says it keeps the folder/subfolder structure, so it helps users keep the structure organized after the conversion.
3. Live Preview and Filtering
Preview of OLM data before conversion is offered by the software. This can help users to check the contents of the mailbox and identify the data they want to process instead of blindly converting the whole file.
4. Attributes and Formatting of Email
GainTools maintains OLM email attributes and rich text formatting, according to the official product page. This is useful if you want to keep information such as message details and formatting during the migration.
5. Converting Attachments
OLM to MSG converter supports attachments. This is a very important requirement for business email as a message without its attachments may not provide a complete migration.
6. No Outlook installation needed
One practical aspect, notes GainTools, is that Microsoft Outlook does not need to be installed to do the conversion. This tool can be used as a stand-alone solution for the users who want to create MSG files on the Windows Computer.
7. User Defined Output Location
The software is intended for users to choose the destination for saving the converted MSG data. This can be helpful when sorting output by project, mailbox, department or migration batch.
8. Compatible with Windows
According to the official page, it works with Windows 11, 10, 8.1, 8 and 7, 32-bit and 64-bit.
How to Convert OLM to MSG
Conversion Workflow The conversion workflow is simple, comprising of few basic steps.
Step 1: Download OLM to MSG Converter
Download and install the app on a supported Windows machine.
Step 2: Import OLM file
Run the software and browse the location where Mac Outlook OLM file is stored.
Step 3: Scan & Pre-View
The software scans the OLM file and displays a preview once it is loaded. Look at the available email data and folders.
Step 4: Choose Required Data
Use the selection or filter options to find the emails or folders that you want to convert.
Step 5: Choose MSG as Output
Choose MSG as the destination format and select the destination folder.
Step6 : Start the Conversion
Let's start the conversion. Now, the software exports the chosen OLM email data in MSG format.
details the process as a three-step conversion workflow on its product page. Its broader OLM converter documentation also describes loading the file, previewing data, selecting an export format, choosing a destination and starting conversion.
OLM to MSG Converter Review
Performance is an important factor to consider when choosing email conversion software.
The application is listed as around 3.82 MB by GainTools which is quite small for a desktop migration utility. The product page also mentions that the software does not limit the size of the files for conversion.
Conversion speed may differ depending on factors such as:
- Size of OLM file
- No. of Emails
- Volume of attachment
- Complexity of the folder
- Computer hardware
- Disk space available
- Environment Windows
Hence, it is advised for users with especially large OLM archives to test the trial edition with their own data before making a large migration.
Pros
- Convert OLM emails to MSG format
- And supports email attachments.
- Preserves folder and subfolder structure
- Offers live preview
- Data filtering provided
- Microsoft Outlook is not needed
- Supports e-mail properties and rich-text formatting
- The output location can be selected by the user.
- Windows 11/10/8.1/8/7 Compatible
- Offers a free trial for testing
Cons
1. It is an application for Windows
2. The free trial has a conversion limit
Conclusion
GainTools OLM to MSG Converter is developed with a single purpose to convert Mac Outlook OLM email data to Windows supported MSG files. It features preview, filtration, attachment handling, folder preservation and email attribute retention.
Additionally, the software offers a trial version which allows users to test the conversion process before purchasing the lifetime license.
The important things to look for while choosing the best OLM to MSG converter software are Compatibility, Data preservation, Attachment handling, Folder structure, Preview, Limitation of trial, and Condition of source OLM file. You can try out the software with a representative OLM archive to determine if it meets a specific migration need.
Frequently Asked Questions
1. What is GainTools OLM to MSG Converter?
This is a Windows based utility that helps you to convert Mac Outlook OLM emails to MSG format for Windows Outlook.
2. Do I need Microsoft Outlook to use GainTools?
No, there is no need for installing Microsoft Outlook to perform conversion, GainTools says.
3. How to Convert GainTools OLM Attachments?
Yes. The software supports converting OLM emails with attachments.
4. Maintains OLM folder structure?
Yes. GainTools claims it maintains folder and subfolder hierarchy during conversion.
5. Is it possible to preview OLM data before conversion?
Yes. The software allows you to preview data as it is collected and also has filtering capabilities.
6. Is it possible to convert corrupted OLM files?
The OLM conversion documentation by GainTools is about OLM files in a good state. There is no indication that corrupted OLM recovery is a supported feature of OLM-to-MSG converter.
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