Open MSO file

MSO files: what are they and how do I open them?

Are you facing difficulties opening unknown files on your computer, or wondering exactly what this file is?
We've got the information and best software solutions for opening these files effortlessly.

.mso file type #1: Microsoft Organization Chart

mso file extension is utilized for organizational charts made with the Microsoft Organization Chart software tool, which was included in Microsoft Office 2000 and its predecessors.

Further details:

MSO file is a chart created by older versions of Microsoft Organization Chart, a program that was used to create organizational charts.

It contains data about the structure of an organization made in the Office 2000, including the relationships between different departments and individuals.

The file can be embedded into Microsoft Office documents, such as Word, Excel, and PowerPoint. However, Microsoft Organization Chart has been replaced by newer diagramming software like Microsoft Visio.

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Microsoft Organization Chart

Add-in for Microsoft Office

.mso file type #2: ActiveMime object

Files with mso file extension might also be found as ActiveMime objects, some sort of spin-off of ActiveX content.

Further details:

The mso file extension was also reported to be used for ActiveMime objects, some sort of 'spin-off' of ActiveX content.

ActiveMime is simply zlib-compressed data starting at offset 0x32, then a standard OLE file with the VBA macro project.

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Microsoft Windows

A series of operating systems developed by Microsoft

.mso file type #3: MedlySound module

An mso file extension is related to the MedlySound. An mso file contains module.

Further details:

The mso file extension is associated with MedlySound, a very elaborated editor.

Earlier audio routines called 'Future Player' (Hybris and Imploder3). Imploder4 music is made with Medley 1.0. created by Paul van der Valk. Old file extension.

.mso file type #4: OLE web page storage stream

Files with mso extension can be found as special attachment for Microsoft Word documents send through e-mail to MS Outlook. Contains data to properly render the document as a HTML webpage in Outlook.

Further details:

File extension mso seems to have been in the past used for a special attachment format generated by earlier versions of Microsoft Word (and possibly other MS Office programs) in conjunction with earlier versions of Microsoft Outlook.

Typically this happens when Word is used as email editor, the document is being send out as the email body which is in HTML format. Usually found as oledata.mso file.

The mso file contains necessary information to properly render the attachment in the message in its originating program. This happens when the file is opened in Outlook 2000 and 2003, and was fixed in 2007 and later. However the "problem" is generated by the sender, not by the recipient.

If you have Outlook installed, you will not see this file, as the document will be rendered properly in HTML using the data from oledata.mso.

However if your computer does not have Outlook installed and you use other mail client, you will see the oledata.mso file as an attachment.

The mso file does not contain the actual document, which can be either found in the body of the e-mail message, or as another attachment as .doc file.

You can disable this function in Word by:

Open Microsoft Word
Go to Tools ► Options… ► General tab
Click the button E-mail Options…
You can set the HTML filtering options on the General tab
Confirm it by OK

This is not exclusive to Word, but just happened mostly with the word-processor. But same files were for example generated by FrontPage or when saving documents to office html format and possibly also with broken links to files like filelist.xml, editdata.mso and oledata.mso.

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