Outlook Express can’t open EML attachment, what to do?

I’am trying to open an .eml attachment using Outlook Express, nothing happens when I trying to run .eml file.

This problem may occur if the .eml file type was associated with an installed third-party e-mail software. Either the file may not open or you may receive an error message that states that there is no program associated with this file type.
To resolve this behavior, you can either run the Outlook Express (Msimn.exe executable file) with the /reg option to force Outlook Express to re-register its file types, or re-register the .eml file type in My Computer.

To run the Msimn executable file with the /reg option:

1. Close the Outlook Express if it is launched
2. Click Start (Windows start button), and then click Run item
3. Type in msimn /reg in the Open box, and then click OK button

To re-register the .eml file type in My Computer:

1. Double-click My Computer shortcut on the desktop
2. Open the Tools menu and click Folder Options
3. Click the File Types tab
4. Under Registered file types, click EML Outlook Express Mail Message, and then click Advanced
5. Click Open, and then click Edit
6. Type in the following single line in the Application used to perform action box:
   “C:Program FilesOutlook ExpressMSIMN.EXE” /eml:%1
7. Click OK button, click OK again, and then click Close

Save Attachment Button Is Disabled

Default Outlook Express installation has the security level which do not allow to open and save attached files which can be dangerous for your system.

To enable the access to attachments you can do the following:

1. Run the Outlook Express and choose the Tools menu
2. Click Options and select the Security tab
3. Erase the check-box which named:
   “Do not allow attachments to be saved or opened that could potentially be a virus.”
4. Restart the Outlook Express application.