MBX File Extension
Outlook Express Mailbox
- File Type mbx
- Developer Microsoft
- Popularity
- Application Microsoft Outlook Express
- Category Data Files, Email Program Files
What is a MBX file?
The MBX extension is used by Outlook Express Mailbox and falls under the categories of Data Files and Email Program Files, covering 6246 files.
Microsoft, the developer of the Outlook Express Mailbox (MBX), has released file format and 242 programs designed to handle them.
MBX files are supported by Windows and Mac OS. There are 9 programs available to open a MBX file, including popular tools like Microsoft Outlook Express, Eudora and Pegasus Mail.
Programs that support MBX files
How to open a MBX file?
If you are having trouble opening a MBX file, it usually means the right software is not installed. Choose a program from the list that matches your operating system. Next, visit the official website of the developer, download the software, and install it on your device.
Microsoft Outlook Express, Eudora and Pegasus Mail stand out as the preferred programs to manage MBX files effectively. To get the latest version of Microsoft Outlook Express, open the Microsoft website where a universal installer for all operating systems is available.
After installation, your operating system should automatically open MBX files with Microsoft Outlook Express.
Set Microsoft Outlook Express as the default MBX program
Change Default Program on Mac
- Right click or Control + left click on the desired MBX file;
- Choose "Open in Application" and click "Other";
- Next, at the bottom of the window, you will see the "Enable" menu, in which "Recommended Programs" is selected by default;
- In this menu, select "All Programs", then find Microsoft Outlook Express and check the box next to "Always open in the application."
Set default programs for Windows
- To get started, right-click your MBX file, then choose "Open With" and select "Choose Another Application" from the context menu;
- In the pop-up window, select the Microsoft Outlook Express application;
- Check the "Always use this application" checkbox, and then click "OK" to apply the selected application as the default for opening MBX files.
Solve problems with MBX files
There are some common issues with MBX files that can be resolved easily by making minor adjustments to your software. Below, you’ll find these issues along with practical troubleshooting tips.
How can I determine if my MBX file is damaged?
MBX data files that have become corrupted may display one or more of the following symptoms:
- Microsoft Outlook Express or other programs stop responding or crash when trying to handle the file;
- Error notifications appear during file manipulation;
- When opening the file, errors occur or the inability to access its contents;
- Unexplained MBX file size inflation;
- The file exhibits poor performance during editing operations in Microsoft Outlook Express;
Why does Microsoft Outlook Express quit or crash unexpectedly?
Insufficient software updates are a likely cause of Microsoft Outlook Express crashes. Be sure to install the latest updates for Microsoft products.
Restarting your computer will solve many common problems, which is why it’s the first thing you should do before changing any settings related to the software.
What methods can be used to repair a damaged MBX file?
Launch Advanced Office Repair, Advanced Outlook Express Repair or Advanced Outlook Repair and open the damaged MBX file. Then, choose the "Repair" option from the menu. Allow the recovery process to complete, which will automatically repair the damaged data files.
How to edit a MBX file?
To make changes to MBX files, you need specialized software that allows both opening and editing the data files. Online MBX editors offer fewer capabilities than applications optimized for Outlook Express Mailbox.
Best MBX Editor Software in 2026
Based on these criteria, we have prepared a list of available MBX editors.
| MBX Editor Software | Developer | Platforms | Overall Rating |
|---|---|---|---|
| Netscape Mail | AOL | Windows | 4.9 out of 5 (40 reviews) |
| PocoMail | Poco Systems | Windows | 4.9 out of 5 (40 reviews) |
| Eudora | QUALCOMM | Windows, Mac OS | 4.8 out of 5 (39 reviews) |
| Pegasus Mail | David Harris | Windows | 4.8 out of 5 (42 reviews) |
| Microsoft Outlook Express | Microsoft | Windows | 4.4 out of 5 (39 reviews) |