Windows
Compatible applications
Quick Facts
Basic information about this file format
Extension
.MSG
File Type
Microsoft Outlook Message File
Category
Data
Best first step
Use compatible software
Quick Summary
A practical overview of the .msg file format
The MSG file format is a proprietary binary file format developed by Microsoft used primarily by Microsoft Outlook to store individual email messages, meeting requests, tasks, or other Outlook items. An MSG file encapsulates all the data associated with a single item, including the sender, recipien…
File extension
.MSG
File type
Microsoft Outlook Message File
Category
Data
Recommended action
Open with a trusted compatible app
How to open a .msg file
Start with a trusted app that supports this format
- Check the file extension carefully and confirm that the file name really ends with .msg.
- Use software that supports this file type. If one app does not work, try another compatible program for the same platform.
- Update the application if the file was created by a newer version of the software.
- Scan files from unknown sources before opening them, especially documents, archives, scripts, installers, and executable files.
What is a .msg file?
File extension details and usage information
The MSG file format is a proprietary binary file format developed by Microsoft used primarily by Microsoft Outlook to store individual email messages, meeting requests, tasks, or other Outlook items. An MSG file encapsulates all the data associated with a single item, including the sender, recipient(s), subject, body content (which can be plain text, HTML, or rich text), attachments, timestamps, and any associated metadata. Because it stores a complete, self-contained message object, it is often used for archiving specific communications or for transferring single messages between Outlook users. The structure of MSG files is based on the Microsoft Outlook Message Store (OMS) format, which is a structured storage file format. While primarily associated with Outlook, other email clients or specialized forensic tools may have limited ability to read or interpret the contents of these files, though full fidelity often requires Microsoft Outlook itself. This format is distinct from PST (Personal Storage Table) or OST (Offline Storage Table) files, which store entire mailboxes or folders.
Software Compatibility
Programs that may open or work with .msg files
macOS
Compatible applications
Linux
Compatible applications
Mobile
Mobile applications
Can .msg files be converted?
Options for saving or exporting this file to another format
In many cases, a .msg file can be converted by opening it in compatible software and using an option such as Save As, Export, or Convert. The available output formats depend on the file type and the application used.
- Use the original software that created the file when possible.
- Check whether the application supports exporting to common formats.
- Be careful with online converters when working with private, business, or sensitive files.
- If conversion fails, the file may be corrupted, incomplete, encrypted, or not actually a .msg file.
Why can't I open a .msg file?
Common reasons this file type may not open correctly
Wrong software
The file may require a specific program that supports the .msg format.
Incorrect extension
The file extension may have been renamed manually, even though the actual file format is different.
Corrupted file
The file may be incomplete, damaged during download, or transferred incorrectly.
Outdated app
Your software may need to be updated before it can open newer versions of this file format.
Frequently Asked Questions
Common questions about .msg files
To open a .msg file, use software that supports this file format.
- Microsoft Outlook
- MSG File Viewer (Third-party tools)
- Kernel MSG Viewer
- Microsoft Outlook for Mac (limited support/conversion often needed)
- Third-party MSG viewers for Mac
Open the file in compatible software and look for options such as Save As, Export, or Convert. If no export option is available, the file may require a specialized converter or the original application that created it.
- Verify that the file extension is correct.
- Install or update compatible software.
- Try another application that supports this format.
- Check whether the file is corrupted, incomplete, or encrypted.
A file extension alone does not guarantee whether a file is safe or unsafe. Only open files from trusted sources, scan unknown files before opening them, and be especially careful with executable, script, archive, and document files.
File safety tips
Use caution with unknown files
Only open files from trusted sources. Before opening a .msg file, scan it with antivirus software, verify that the file extension is expected, and avoid running unknown executable, installer, macro-enabled document, or script files.