.MSO File Extension

File Type 1

Microsoft Office Macro Reference File

Developer Microsoft
Popularity
3.3  |  124 Votes
Category Misc Files
Format N/A

What is an MSO file?

An MSO file is a macro reference file created when saving a Microsoft Office document as a webpage. It contains information about macros and OLE (Object Linking and Embedding) objects included in the original file and may be referenced by the created webpage as a style sheet. MSO files may be viewed with a text editor, but will be unreadable since the contents are encoded.

More Information

Most users will only see the MSO file as an attachment to an email. Do not open the file if it has the ".mso" extension because it most likely contains a virus that will be installed on your computer when opened.

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Programs that open or reference MSO files

Windows
Should not be opened manually
Mac
Should not be opened manually
Updated November 17, 2016
File Type 2

Inline E-mail Attachment

Developer Microsoft
Popularity
2.8  |  35 Votes
Category Misc Files
Format N/A

What is an MSO file?

File sent with Microsoft Word 2000 e-mail attachments; often named "Oledata.mso;" contains information that allows the attachment to be rendered within the e-mail message.

More Information

The Oledata.mso file will appear as a separate attachment on computers that do not have Microsoft Outlook 2000 or later installed.

Programs that open MSO files

Updated January 4, 2008

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