Problem: just this month they started sending in .xlsx format, which is the 2007 Excel format. I don't have Excel anyway, I use OpenOffice for those, but OpenOffice doesn't want to handle this particular format (it has issues with .docx, too, which is the same Office release, so I am not too shocked).
Anyone know of a good viewer or file converter I could download for free? I have Mac OS X 10.4.11, and most of the stuff I'm finding so far is for an older Mac OS or for Windows only. :(