I have a Powerbook early 2008 (4,1), it's been running snow leopard with two versions of Office available (X and 2008). After installing 2008 I noticed that the old Office documents (doc & xls) wouldn't open with the Office 2008, well they open but most of the content is missing. They still open fine with the Office X.
I have lived with this for some time because I have had the old version version of Office X available.
Today I upgraded the Mac to Lion..........oh dear, the old Office X no longer runs and so I am unable to open my old Office documents.
I also have a MacBook Pro (2009) running Lion and it also has Office 2008. I have transferred a couple of the problem documents from the other machine and they open just fine.
I am confused. Both machines have versions 12.2.9 of Word & Excel.
Any suggestions?

I realize this is somewhat of a pain, but the fix for this type of Office malfunction usually is to uninstall it with the Remove Office tool, followed by a reinstall and the application of all available updates.

Thanks I will try that

Yes it did the trick.
Thanks

You're welcome. Thanks for letting us know!

Microsoft insisted on bringing the joys of the windows registry to the mac, instead of recoding their mac port of office to use a normal mac preferences system. As a result, there's a ~150-500k file on your computer that is office's registry. If you delete the file, it "grows back" at about 56k and nothing will work right until you do something about it. Usually office apps crash on launch, or will hang during startup.

And same as on windows, it can get corrupted and cause severe malfunctions. And same as on windows, clean reinstallation is the easiest way to fix it.

When you have to support a few hundred macs with office on them, you quickly learn to keep a backup copy of the few variations on that file. Office problem? Replace the registry file from backup. Problem fixed. Much quicker and easier than reimaging the workstation.

iirc it's the "Microsoft Registration Database", somewhere in the Office folder. The file name and path vary with office versions. Except when they don't (like 2008 to 2011) and then all hell breaks loose when you try to have both apps installed at the same time.

Currently I find mine in ~/Library/Preferences/Microsoft/OLE Registration Database 11

I don't have Office 2011 but the path (for Office 2008) is ~/Library/Preferences/Microsoft/Office 2008/OLE Registration Database 2008. There is also a file named OLE Registration Database 2008 (Converter) in the same location.

MS Office is not crashing for me so I assume that everything is hunky-dory.