Mac users will have to wait a bit longer if they wish to read or edit documents created with the new Open XML formats in Office 2007. Microsoft has delayed an update for Office 2004 for Mac until two months after the release of Office 2008 for Mac.

In the meantime, a standalone converter is being offered in beta, but its functionality is limited. It will convert .docx files from Office 2007 to the basic rich text format (RTF), which is compatible with both Office v.X and Office 2004. Microsoft recommends re-saving the document as a .doc before sending it to others.

If colleagues wish to collaborate on a document, the converter won't do much good. Instead, the Office 2007 users will need to opt to save the file in the older Office 97-2003 standard. Because of RTF's limitations, advanced documents could lose formatting and other elements in the conversion process.

Microsoft says it chose RTF for the beta because it was a "highly convenient" intermediate format.

"So far the converter is doing great, but then in most cases I tend to only need to read and review the documents rather than co-edit them (product plans, service agreements, draft letters, staff communications and the like)," explained Geoff Price from Microsoft's Mac Business Unit. "For active collaboration on critical or complex documents - e.g. where getting the formatting, tables etc. correct is essential - you'll want to continue to work with the older (.doc) format from the start."

The Microsoft Office Open XML File Format Converter for Mac began its life as an internal test tool at the Redmond company during the development of Office 2008. However, it was soon noted that the tool would make for a decent stop-gap measure for customers due to the delays in preparing a compatibility update for Office 2004.

"Why wait until after we ship to release the final converters? The converters include and rely upon the same new code that lives in Office 2008 (so you're getting early access to some of the new code today - running natively as a Universal Binary, of course). As the code improves in the applications, so will the converters improve, and as a result the converters will not be final until Office 2008 is also fully complete and fully tested," added Price.

Microsoft plans to update the converter over the summer, adding support for PowerPoint and Excel documents. Upon their final release, both the Office 2004 update and standalone converter will be able to seamlessly read and export to the Open XML formats.

The first beta of Microsoft's Office Open XML File Format Converter for Mac is available for download via FileForum.