Introduction to new file name extensions and Office XML Formats

The Microsoft Office system introduces a new file format that is based on XML. It is called Microsoft Office Open XML Formats and applies to Microsoft Office Word, Microsoft Office Excel, and Microsoft Office PowerPoint. This article summarizes key benefits of the new format, describes what the new file name extensions are, and discusses how you can share the Office release files with people who are using earlier versions of Office. In this article

What are the benefits of Office XML Formats?

What are the new file name extensions?

Can different versions of Office share the same files?

What are the benefits of Office XML Formats?

The Office XML Formats introduces a number of benefits - not only for developers and the solutions that they build, but also for individual people and organizations of all sizes:

• Compact files Files are automatically compressed and can be up to 75 percent smaller in some cases. The Office XML Formats uses zip compression technology to store documents, offering potential cost savings as it reduces the disk space required to store files and decreases the bandwidth needed to send files via e-mail, over networks, and across the Internet. When you open a file, it is automatically unzipped. When you save a file, it is automatically zipped again. You do not have to install any special zip utilities to open and close files in the Office release.
• Improved damaged-file recovery Files are structured in a modular fashion that keeps different data components in the file separate from each other. This allows files to be opened even if a component within the file (for example, a chart or table) is damaged or corrupted.
• Easier detection of documents that contain macros Files that are saved by using the default "x" suffix (such as .docx and .pptx) cannot contain Visual Basic for Applications (VBA) macros or ActiveX controls, and therefore do not pose the security risks associated with those types of embedded code. Only files whose file name extension ends with an "m" (such as .docm and xlsm) can contain VBA macros and ActiveX controls, which are stored in a separate section within the file. The distinct file name extensions make it easy to distinguish files that contain macros from those that don't, and make it easier for antivirus software to identify files that contain potentially malicious code. In addition, IT administrators can block the documents that contain unwanted macros or controls, making it safer to open documents.
• Better privacy and more control over personal information Documents can be shared confidentially, because personally identifiable information and business-sensitive information, such as author names, comments, tracked changes, and file paths can be easily identified and removed by using Document Inspector. For details, see Remove hidden data and personal information from Office documents.
• Better integration and interoperability of business data Using Office XML Formats as the data interoperability framework for the Office release set of products means that documents, worksheets, presentations, and forms can be saved in an XML file format that is freely available for anyone to use and to license, royalty free. Office also supports customer-defined XML Schemas that enhance the existing Office document types. This means that customers can easily unlock information in existing systems and act upon it in familiar Office programs. Information that is created within Office can be easily used by other business applications. All you need to open and edit an Office file is a ZIP utility and an XML editor.

Note You might sometimes need to save your files in the binary file format that was used in earlier versions of Office. For example, you might be working on a document with someone who has an earlier version of Office. For this reason, the Office release still allows you to save files in in binary format.

Before you decide to save your file in a binary format, read the Can different versions of Office share the same files? section of this article.

What are the new file name extensions?

By default, documents, worksheets, and presentations that you create in the Office release are saved in XML format with new file name extensions that add an "x" or an "m" to the file name extensions that you are already familiar with. The "x" signifies an XML file that has no macros, and the "m" signifies an XML file that does contain macros. For example, when you save a document in Word, the file now uses the .docx file name extension by default, rather than the .doc file name extension.

When you save a file as a template, you see the same sort of change. The template extension used in earlier versions is there, but it now has an "x" or an "m" on the end. If your file contains code or macros, you must save it by using the new macro-enabled XML file format, which adds an "m" for macro to the file extension.

The following tables list all of the default file extensions in Office Word, Office Excel, and Office PowerPoint.

Word

Excel

PowerPoint

Can different versions of Office share the same files?

The Office release allows you to save files in the new Office XML Formats and in the binary file format of earlier versions of Office. The Office release includes both compatibility checkers and file converters to facilitate file-sharing between different versions of Office.

Opening existing files in the Office release You can open and work on a file that was created in an earlier version of Office, and then save it in its existing format. Because you might be working on a document with someone who uses an earlier version of Office, you don't want to introduce any features supported only by the Office release. The Office release uses a compatibility checker that checks to make sure that you have not introduced a feature that an earlier version of Office does not support. When you save the file, the compatibility checker reports those features to you and then allows you to remove them before continuing with the save.

For more information about using the Office release to open documents, workbooks, and presentations created in earlier versions of Word, Excel, and PowerPoint, see the links in the See Also section.

Opening the Office release files in earlier versions of Office You can open and edit a Office release file in an earlier version of Word, Excel, or PowerPoint by downloading the necessary file converters. On the computer with an earlier version of Office, go to the Download Center and download the Microsoft Office Compatibility Pack for Office Word, Excel and PowerPoint File Formats.

Important For the converters to work, your version of Microsoft Office must first be updated to one of the service packs listed here. After you have installed the service pack for your version of Office, then download the converter.

• Microsoft Office 2000 Service Pack 3
• Microsoft Office XP Service Pack 3
• Microsoft Office 2003 Service Pack 1

For more information about opening the Office release documents, workbooks, and presentations in earlier versions of Word, Excel, and PowerPoint, see the links in the See Also section.

See also:

• Open a Word document in an earlier version of Word
• Use Word to open documents created in previous versions of Word