What is Word's Compatibility Mode?
Simon Jones explains how Microsoft's Words Compatibility Mode works
New users of Office 2007, 2010 and 2013 are often confused by the words "Compatibility Mode" that appear in the application title bar when they open certain documents.
A reader named Bonnie recently emailed me as she’d just upgraded to Office 2010: "Not sure what this is but someone mentioned I should change it. I don’t know what it is, nor how to get rid of it? I did look on the internet and found something to try, but it didn’t work. Can you explain to me why I need to change this and if so, how, since I’ve seen this in the title bar of some documents when I open them?"
Features introduced in the newer applications will usually be gracefully downgraded to work with the older version
You’ll see Compatibility Mode whenever you open a document that was saved in Word 97-2003 or Word 2007 format, and it means that not all the features of your version of Word are available to you in that document since they couldn’t be saved in that format. Compatibility Mode is used to ensure that new features of later versions aren’t accidentally introduced into earlier documents, unless you explicitly choose to "upgrade" them. This means that documents created in Word 2007 and before will always display and print correctly in that version of the application, whether or not they’ve been edited in a later version.
If you want to use newer features, or take advantage of the reduced file size or increased robustness of a new format, then click File | Info | Convert. There may be minor layout changes as part of this process; see the Microsoft Office website for information on which features aren’t available in Compatibility Mode.
Word 2010 DOCX files can be opened by Word 2007 and by Word 2003, 2002 (XP) and 2000 if the user has installed the Compatibility Pack, which has been available since late 2006, so there shouldn’t be any problems if you do decide to convert a document to Word 2010 format.
Plus, you can always use File | Save As to downgrade the document to 97-2003 format again later, if necessary. (Again, this may involve minor layout changes, so it’s best to check the document after converting if you’re worried. Just open the original document and the converted one side by side to do a visual check that everything is legible and where you expect it to be.) You can get the Compatibility Pack for Office 2000, XP and 2003 from the Microsoft Support site.
When you use the Compatibility Pack to open new format documents in older versions of Office, you’ll find that any features introduced in the newer applications will usually be gracefully downgraded to work with the older version: for instance, Smart Art will be replaced by a simple image of what the Smart Art should look like. You can reposition or resize the image using the earlier application, but you can’t edit the individual elements that make up the Smart Art.
Usefully, however, when you save your edited document in OOXML format and open it with Office 2007 and above, that Smart Art will become editable in its new position, or at its new size. This is one reason for sticking with the OOXML file formats (docx, xlsx, pptx) and not downgrading them to the older binary file formats; if you do that, the change from Smart Art to a static image becomes permanent.