How to Open MSG Files on Mac: A Comprehensive Guide

If you use a Mac, chances are you‘ve received an email attachment with the .msg file extension at some point. You may have even double-clicked it by habit, only to be puzzled when your Mac reports that there‘s no application set to open the file. That‘s because .msg is the format used by Microsoft Outlook on Windows for storing email messages, calendar events, contacts, tasks and other data. And while Macs can do most things Windows PCs can, opening this particular file format is not one of them.

This incompatibility can be a major headache, especially in a world where Mac adoption is growing in the workplace. According to IDC, Macs accounted for 23% of enterprise notebook shipments in 2020, up from just 17% in 2019. Yet Windows still dominates the workplace overall, with over 1 billion PCs in use globally compared to about 100 million Macs. That means if you‘re a Mac user, sooner or later you‘re going to receive an important .msg file from a colleague on Windows that you need to open.

Luckily, there are several ways to bridge this file format divide and access the contents of .msg files on a Mac. As a Mac software expert who‘s supported hundreds of business and home users over the years, I‘ve had to tackle this problem many times. In this guide, I‘ll share the six most effective methods I‘ve found, along with step-by-step instructions and tool recommendations.

Method 1: Run Outlook for Windows on Your Mac

The most powerful way to open .msg files on a Mac is to install Windows and use the Windows version of Outlook. This gives you 100% compatibility, not just for viewing .msg files, but for full synchronization of mail, calendars, contacts and tasks with your Windows-using colleagues.

While this may sound daunting, Apple actually makes it fairly easy to install Windows on a Mac. If you have a recent Intel-based Mac, you can use the built-in Boot Camp Assistant to partition your hard drive and install Windows 10 alongside macOS. This effectively lets you dual-boot, with the option to run either Windows or macOS each time you start up your Mac.

Here‘s how the Boot Camp setup process works:

1. Check that your Mac has at least 64GB of free disk space for Windows
2. Insert a USB flash drive with at least 16GB of space
3. Open Boot Camp Assistant (in Applications > Utilities) and click Continue
4. Select "Create a Windows 10 or later install disk" and click Continue
5. Select your USB drive, click Continue, and wait for the Windows 10 installer to be downloaded
6. Select "Install Windows 10 or later version" and click Continue
7. Adjust the disk space allocated to Windows using the divider (I recommend at least 128GB)
8. Click Install and wait for your Mac to restart into the Windows installer
9. Follow the prompts to install Windows, then install Apple‘s support software
10. When installation is done, your Mac will boot into Windows by default
11. To return to macOS, restart your Mac and hold the Option key to choose your startup disk

While Boot Camp offers the best performance, it requires rebooting to switch between Windows and macOS. Another option is to use virtualization software like Parallels Desktop or VMware Fusion. These let you run Windows in a virtual machine within macOS, so you can use Windows and Mac apps side-by-side. The downside is reduced performance, especially for resource-intensive apps.

Both Boot Camp and virtualization require a valid Windows 10 license, which costs $139 if you don‘t already have one through school or work. Parallels and VMware have their own costs as well, at $79.99 and $149 respectively. Whether it‘s worth paying depends on how often you need to work with .msg files and other Windows-only formats.

If you do go this route, I highly recommend using an Office 365 subscription to get the latest version of Outlook for Windows. Office 365 Business plans that include desktop Office apps start at $8.25 per user per month with an annual commitment.

Method 2: Use the Outlook Web App

For many people, accessing their email through a web browser is already a daily routine. If your organization uses Microsoft 365 or a self-hosted Exchange server, you can use the Outlook Web App (OWA) to view .msg files right in your browser, no Windows required.

Here‘s how it works:

1. Sign in to your Microsoft 365 or Exchange account at outlook.office.com
2. Click "New Message" to compose a new email
3. Drag your .msg file into the body of the message, or click the attachment icon to browse for it
4. Once the .msg file is attached, double-click it to open it in Outlook‘s built-in .msg preview

The Outlook Web App‘s .msg preview is surprisingly full-featured, with support for formatted text, images, attachments, and even the ability to reply to or forward the original message. You can also download the attached .msg file for safekeeping.

Of course, this only works if you have a Microsoft 365 or Exchange account to begin with. If you‘re using Gmail or another email provider, you‘re out of luck. There‘s also no way to batch convert multiple .msg files through OWA – you have to preview them one at a time.

Method 3: Install Mozilla SeaMonkey

For a free, open-source option, look no further than Mozilla SeaMonkey. This little-known internet suite is a successor to the Netscape Communicator package and includes a web browser, email client, IRC chat client and HTML editor.

While SeaMonkey may seem like overkill just for opening .msg files, it has a hidden talent: the included email client can open and display .msg files directly, without any add-ons or conversions.

Here‘s how to do it:

1. Download SeaMonkey from the official website at seamonkey-project.org
2. Mount the SeaMonkey DMG file and drag the app icon to your Applications folder
3. Open SeaMonkey and select "Mail & Newsgroups" from the Window menu
4. If prompted to set up an email account, click Cancel, then Exit
5. Go to File > Open File and select the .msg file you want to view

SeaMonkey uses the same rendering engine as Thunderbird to display .msg files, so the quality is quite good. You can view the message body, subject, sender, recipients, and any attachments. Replying and forwarding are also possible if you‘ve configured an email account.

The downside of SeaMonkey is that it‘s a bit clunky and dated compared to modern email clients. It also includes a lot of features most people don‘t need, like the chat client and HTML editor. And while it‘s still being maintained by volunteer developers, it doesn‘t get nearly as much attention or updates as Firefox or Thunderbird.

Still, if you only need to view the occasional .msg file and don‘t want to pay for software, SeaMonkey is a solid choice. Just be aware that you may need to dig through some advanced settings to get it working just the way you want.

Method 4: Try a Third-Party MSG Viewer

If you‘d prefer something more modern and Mac-like than SeaMonkey, there are several third-party applications designed specifically for viewing .msg files on macOS. These generally offer a more polished experience, with features like drag-and-drop support, Quick Look integration, and the ability to reply to and forward messages.

Some of the most popular MSG viewers for Mac include:

App	Price	Key Features
MSG Viewer for Outlook	$17.99 / Free trial	Native Mac design, supports drag-and-drop, can save attachments
Klammer	$3.99	Minimalist design, Quick Look support, compatible with macOS Big Sur
Sysinfo MSG Viewer	$29 / Free trial	Supports batch viewing of multiple files, can save to PDF/HTML/TXT
Winmail.dat Opener	Free	Opens .msg and winmail.dat files, extracts attachments, in-app purchases

In general, I‘ve found dedicated MSG viewers to be the easiest way to quickly access .msg files on a Mac. Installation is a breeze, there‘s no configuration necessary, and the user interfaces are all straightforward. Most include a free trial, so you can see if a particular app fits your needs before buying.

However, there are a couple downsides to MSG viewer apps. First, many only allow you to view the contents of the .msg file, not reply to or forward the message using your own email client. Second, they generally don‘t support batch processing or email imports – you have to open files individually. Finally, some apps haven‘t been updated in several years and may not offer full compatibility with the latest versions of macOS.

If you receive .msg files regularly and just need to view them, an MSG viewer app is definitely worth the small investment. I wouldn‘t rely on them as a complete replacement for Outlook or Apple Mail, but they‘re great for occasional use.

Method 5: Convert .MSG to Another Format

For a more permanent and compatible solution, you can try converting MSG files to another format like EML. EML files can be opened in most email clients on Mac, Windows and Linux, including Apple Mail and Outlook for Mac.

There are a few different ways to convert .msg to .eml on a Mac:

1. Use an online converter like CoolUtils MSG to EML. Just upload your .msg file, wait for it to be converted, and download the resulting .eml file. This is convenient for one-off conversions, but I don‘t recommend uploading sensitive email data to third-party websites.

2. Install a file format converter app like Amadeus Pro ($59.99) or Macsome EML Converter Pro ($39.95). These support batch conversion of multiple .msg files at once and have a few customization options, but are overkill if you only work with .msg files occasionally.

3. Use a command line tool like msg-converter. This is a free Python script that can convert .msg files to .eml, .html, .json and other formats. It‘s very powerful and flexible, but requires some technical know-how to install and use.

Here‘s an example of how to use msg-converter in the Terminal:

pip3 install msg-converter
msg_converter -i input.msg -o output.eml

In my experience, online converters and command line tools are the most cost-effective options for most users. They‘re not as full-featured as paid converter apps, but get the job done for occasional use. Just be sure to double-check the converted .eml file in your email client, as some formatting and attachments may not convert perfectly.

Method 6: Change the File Extension

Finally, here‘s a little trick that sometimes works if the .msg file was generated by an app other than Outlook. Some email clients and tools label their messages as .msg even though they‘re really in the more standard .eml or plain text format. In these cases, you may be able to open the file just by changing the extension.

To try this:

1. In Finder, right-click on your .msg file and select "Get Info"
2. In the Name & Extension section, delete .msg and replace it with .eml or .txt
3. Close the Info window and double-click the file to open it

If you‘re lucky, the file will open right up in Apple Mail or TextEdit. If not, you‘ll get an error that there‘s no application set to open the file. In that case, you‘ll need to use one of the other methods described above.

Obviously, this hack doesn‘t work for true Outlook .msg files – those will just show garbled text and HTML tags if you try to open them as .eml. But it‘s worth a shot if other methods fail, and only takes a few seconds to try.

Wrapping Up

While dealing with .msg files on a Mac can be frustrating, I hope this guide has shown you that there are several ways to work around the incompatibility. Whether you prefer to run Windows on your Mac, find an alternate email client like SeaMonkey, invest in an MSG viewer app, or convert files to a different format, you have options.

Here‘s a quick summary of when to use each method I‘ve covered:

• Running Windows: Best for full compatibility if you frequently work with .msg files and other Windows-only formats. Requires a Windows license and some setup.
• Outlook Web App: Handy for Microsoft 365/Exchange users who already use OWA and only need to view the occasional .msg file.
• SeaMonkey: A free, open-source option for viewing .msg files, but a bit clunky and dated.
• MSG Viewer Apps: Easiest way to quickly view .msg files on a Mac, but with limited ability to reply/forward messages. Many are paid apps.
• File Converters: Ideal for converting .msg to a more compatible format like .eml for use in Apple Mail or Outlook for Mac. Results may vary.
• Changing Extensions: A long shot, but worth trying if you suspect the .msg file isn‘t really from Outlook.

Personally, I keep a copy of SeaMonkey around for a quick look inside .msg files people send me. If it‘s an important message I know I‘ll need to reference later, I‘ll convert it to .eml using msg-converter so I can file it away in Apple Mail. And if I was in a job where I needed full Outlook for Windows functionality all the time, I‘d probably set up Boot Camp or Parallels to run it right on my Mac.

Your mileage may vary, of course. And if you‘ve found another tool or trick for handling .msg files that I haven‘t mentioned here, I‘d love to hear about it! Feel free to share your experiences and suggestions in the comments below.