It has been about a week since Microsoft released the Office 2007 Beta 2 Technical Refresh and it is running great for me. By default Office 2007 is setup to use the new file format that Microsoft came out with which is much more efficient than the old format. I have noticed that my file sizes are typically 50%-75% less than the original file.
If you are unaware of the new file format here is a list of file extensions and what they represent:
Word
- .docx–Microsoft Office Word 2007 document
- .docm–Microsoft Office Word 2007 macro-enabled document
PowerPoint
- .pptx–Microsoft Office PowerPoint 2007 presentation
- .pptm–Microsoft Office PowerPoint 2007 macro-enabled presentation
- .potx–Microsoft Office PowerPoint 2007 template
- .potm–Microsoft Office PowerPoint 2007 macro-enabled template
- .ppsx–Microsoft Office PowerPoint 2007 show
- .ppsm–Microsoft Office PowerPoint 2007 macro-enabled show
Excel
- .xlsb–Microsoft Office Excel 2007 binary workbook
- .xlsx–Microsoft Office Excel 2007 workbook
- .xlsm–Microsoft Office Excel 2007 macro-enabled workbook
- .xltx–Microsoft Office Excel 2007 template
- .xltm–Microsoft Office Excel 2007 macro-enabled template
- .xlam–Microsoft Office Excel 2007 add-in
I didn’t start using the new file format until I noticed that Microsoft had released an add-on for Office 2000, XP, and 2003 and would let me open/save files with these extensions. Here are the direct download links for the add-on that you need to install (which can also be found on the converter homepage):

I have installed this into my MS Office 2003 (with both SP1 and SP2 and all latest updates). Unfortunately, this beta extension has some bugs:
1.
The default filter in Word’s File Open/Save dialog is “All Word Documents”, but it doesn’t list those new .DOCX files. :(
While corresponding filter in Excel DOES! (for .XLSX and .XLSB).
2.
When ANY Excel file (even empty one!) is saved into .XLSX/.XLSB formats, there is warning shown:
But it DOESN’T show this stupid warning when OPENING those files, only when SAVING.
At the same time, Word saves and opens .DOCX files without any warnings.
they really gone wild with the extensions names. does it mean that in office 2010 will have
MY DOCUMENT NAME.Microsoft Office PowerPoint 2010 macro-enabled presentation
?
I don’t think the extensions will be quite that long in Office 2010. :D
It’s still quite a big step from “.pptx” to “.Microsoft Office PowerPoint 2010 macro-enabled” :lol:
I’m not going to use this yet though, because I start Uni in a weeks time and I doubt they’ll have the stuff to open these file types. It would be nice to see how efficient they were though.