GainTools EML to PST Converter Review (2026): Is it the Right Outlook Migration Solution?

Introduction

EML is one of the most popular email file formats and is supported by applications like Windows Live Mail, Mozilla Thunderbird, eM Client, Outlook Express, Windows Mail and many other desktop email clients. This format works well for storing individual email messages, but it is less useful if users want to migrate their data to Microsoft Outlook. Outlook cannot open EML files directly, as Outlook stores mailbox data in PST files and needs to convert the files first.

There are manual methods to transfer EML emails to Outlook, but it is a lengthy and tedious process. Importing emails one by one can be an inconvenient process for users who have to deal with hundreds or thousands of files. There is also the possibility that you can lose your email formatting, attachments or folder organisation during the process.

To check its efficiency in handling such migration, I tried the GainTools EML to PST Converter with different sets of EML files that I collected from different email applications. I wanted to test the software's performance, conversion accuracy, ease of use, speed, and reliability in terms of converting EML files to Outlook PST format.

In this review, I am going to tell you about my full experience with the software, share its most useful features, compare it with the old manual way and note its pros and cons. If you need a reliable email migration tool for moving EML files to Microsoft Outlook, this review will assist you in determining if this software is worth your consideration.

Why do users need an EML to PST Converter tool?

With its sophisticated mailbox management, business-friendly features and tight integration with the Microsoft ecosystem, many user and organisations eventually switch from desktop-based email clients to Microsoft Outlook. Outlook, however, cannot handle large numbers of stand-alone .eml files directly.

This problem is solved by using a special email conversion utility that converts EML messages to Outlook-compatible PST files without losing important mailbox information. This simplifies migration and makes it less prone to manual errors.

Such software is especially helpful for:

• Organizations migrating to Microsoft Outlook.

• IT administrators performing mass email migration.

• Lawyers putting their email records in a file cabinet.

• Merging old e-mails for businesses.

• Users upgrading to Outlook individually.

Instead of using manual methods, users can convert entire folders, retaining the original mailbox structure, in a single operation with professional tools.

What Is GainTools EML to PST Converter?

GainTools EML to PST Converter is a Windows-based mailbox conversion tool to convert EML email files into Microsoft Outlook PST format. The software can convert one email message or convert a large number of emails at a time, so it allows users to transfer complete folders without losing the original email content.

The tool is designed to keep all the important email properties during the conversion, like message formatting, attachments, from and to information, subject, time and date and the folder structure.

One of the major benefits is that the application provides a straightforward workflow, thus making it suitable for both technical professionals and users with little migration experience. The software is designed to do the process efficiently and without unnecessary complexity, whether you are migrating a couple of emails or a large email archive.

Features I Found in Testing That Make a Difference

1. Batch Conversion Saves Lots of Time

One of the features that stood out during testing was the ability of the software to process a large number of EML files at once.

I just added a whole folder of hundreds of messages instead of picking individual emails. The app handled all the supported files automatically and converted them together, which made the migration faster than manual methods.

This feature alone can save hours of work for organisations with years of archived emails.

2. Keeps the Entire Email

The converted Outlook PST retained in my testing:

• Sender information

• Recipient Details

• Subject Lines

• HTML templates

• Email body formatting

• Inline Images

• Attachments

• Date and time details

Each converted email was a near copy of the original version, which is important when you need to maintain business communications or legal documents.

3. Folder structure stays organised

Many conversion utilities are good at migrating emails but do not keep the original folder hierarchy.

Luckily, this software preserved the entire folder structure during the conversion.

Nested folders were preserved, so it was easy to find emails after importing the PST file into Microsoft Outlook. This is especially useful for users managing project- or department-wise email archives.

4. Simple interface for all users

But the other thing I liked was the clean user interface.

The app doesn’t offer superfluous technical options, but instead leads users through a straightforward conversion process.

Even a person doing mailbox migration for the first time can understand the workflow without going through extensive documentation.

The layout overall is well organised, and the buttons are clearly labelled so you don't get confused when you are using it.

5. Compatible with Multiple EML-Based Email Clients

Not all users generate EML files with the same email application.

I tried the software and found it supports EML files generated from various popular email clients, including:

• Windows Live Mail

• Thunderbird

• Windows Mail

• Outlook Express

• eM Client

• Other Applications Supported by EML

Due to this wide compatibility, it is a viable email migration solution for users moving from other platforms.

6. Standalone Conversion without Complex Configuration

One of the useful advantages is that the software does conversion process without any complicated configuration.

After adding the EML files, users just have to select PST as the output format, choose the destination folder and start conversion.

The streamlined workflow provides solid conversion results while reducing user interaction.

How to Use This Professional Converter

Step 1: Download and Install the Software

Step 2: Add Your EML Files or Folder

Step 3: Select PST as the Output Format

Step 4: Configure Required Options

Step 5: Initiate the Conversion Process.

System Requirements

Operating System: Windows 11, 10, 8.1, 8, 7, Vista & XP

Processor: 1 GHz or Faster

RAM: 2 GB minimum (4 GB recommended)

Hard Disk Space: At least 100 MB of free space

Microsoft Outlook: Required to open the created PST file.

Supported Input: EML Files

Output Format: Outlook PST Files

My Practical Experience

To have an idea about how efficient the software is, I created a test environment with almost 650 EML files collected from Thunderbird, Windows Live Mail and eM Client. The collection contained simple text emails, HTML newsletters, emails with multiple attachments, embedded images and multiple deep folder hierarchies.

It was easy to install and only took a few minutes. So I opened the software, and I decided to import the whole email folder instead of choosing single files. The application scanned the folder and displayed all available emails without any errors.

Once you have selected PST as the output format, the process of conversion begins immediately. The software was stable and responsive throughout the operation without freezing or overconsuming the system resources.

When the conversion was done, I imported the created PST file into Microsoft Outlook to check the result.

I rechecked a few things like:

• Email Formatting

• Attachments

• Email subject lines

• Sender and recipient details

• Date & time stamps

• Folder structure

• HTML codes for special characters

They were almost the same as the original e-mails. Attachments opened normally, embedded images displayed correctly, and folder organisation was intact.

It also provided the ability to convert large attachment files, which is a bottleneck for many mailbox conversion software.

The conversion process was generally smooth, accurate and required very little user intervention. The software was a trustworthy choice for users who want to migrate EML email archives into Microsoft Outlook, according to my tests.

Performance Assessment

After performing several conversion tests, here’s how the software fared in various aspects:

In our testing, the software was consistent and was able to convert all the selected emails with no noticeable formatting problems.

Pricing and Licensing

This software offers flexible licensing options for personal and professional users.

The software comes with a free trial version, which allows users to evaluate the functionality before purchasing the full version. The demo version converts a limited number of EML files so that users can check the conversion accuracy.

The licensed version can be used to convert without any restrictions and use all the features.

Given the functionality on offer, batch conversion support and data preservation features, the pricing is good value for users who regularly carry out Outlook migrations.

Pros & Cons

Advantages

• It supports batch conversion of multiple EML files at one time.

• It keeps email formatting, attachments and metadata intact and accurate.

• Maintains the original folder structure during conversion.

• Easy and intuitive interface for beginners.

• Compatible with EML files generated by different email applications.

• Creates Outlook PST files without corrupting data.

• Fast conversion speed, even with large email collections.

• Compatible with all the major Windows OS.

• Evaluation copy. Free trial version. Available before the date of purchase.

Weaknesses

• Available only for Windows OS.

• The trial version allows you to convert a limited number of EML files.

• No MacOS version.

Final Conclusion

I have tested the professional EML to PST Converter with hundreds of EML files of different email clients and found it a reliable and well-balanced email migration utility. The software converted all selected emails to Outlook PST format successfully, with attachments, formatting, metadata and folder hierarchy preserved.

The application is simple, which is the best thing about it. The entire conversion process is performed in a few clicks, so it is suitable for both technical professionals and users with little migration experience. The clean interface ensures there's no confusion, and the batch conversion feature significantly cuts down the time for migrating large email archives.

I was also impressed with how the software performed. The application stayed stable during the test, and conversions were made without any crashes or unexpected errors. The created PST file was opened smoothly in Microsoft Outlook and all the emails were as it was in their original form.

The trial version has limitations on conversion, and the software is only available for Windows users at the moment. But these are relatively minor drawbacks considering the overall functionality and reliability of the software.

If you are looking for a simple and effective Outlook migration tool for accurate results, then this expert conversion tool is surely worth considering. It provides a practical combination of speed, data integrity and ease of use, making it a reliable solution for personal users, businesses and IT professionals alike.

FAQs (Frequently Asked Questions)

Q1. Can I convert multiple EML files into a PST file?

Ans. Yes. The software can convert a folder containing hundreds or thousands of EML files at a time to one Outlook PST file.

Q2. Will my email formatting and attachments be the same after conversion?

Ans. Yes. In the testing process, the software retained the formatting of emails, attachments, embedded images, sender and recipient information, subject lines, timestamps, and folder hierarchy. This helped to ensure that the converted Outlook mailbox was as accurate as possible to the original EML data.

Q3. What email clients does the software support?

Ans. The application supports EML files created by several email clients such as Mozilla Thunderbird, Windows Live Mail, Windows Mail, Outlook Express, eM Client and many other applications that use the EML format.

Q4. Is Microsoft Outlook required for the conversion?

Ans. The software uses its own conversion processor to convert EML files to PST format. But if you want to open, import or access the resultant PST file after conversion is done, Microsoft Outlook is needed.

Q5. Is there a way to try out the software before buying the full version?

Ans. Yes. This tool offers a free trial edition which lets users try the software’s interface, conversion quality and overall performance before upgrading to the licensed version.