My 97-2003 .xls Spreadsheets Keep Losing Their Formatting

[Spencer]

Something has happened over the last two days that is causing my 97-03 .xls spreadsheets to lose their date formatting, accounting formatting, and colors.

I am using Excel 2007 as I have been since the first week it was orignially released a couple of years ago. I am not doing anything different that I am aware of.

Everytime I reopen a spreadsheet it's dates are displayed as the five digit code (i.e. 39966 for 6/2/09), my accounting is showing up as 6232.52 instead of $6,232.52, and my colors are gone.

Everything looks fine when I save and close the document, but then when I open it back up the formatting is gone.

Any ideas??

[Spencer]

After Googling my issue I may have another clue.

Other people are reporting similar issues, oddly most of them also just started having problems in May of 2009. It seems performing a Word 2007 mail merge, which I am doing on the affected documents, may have something to do with it.

Is anyone aware is mail merges causing the inability to reopen a saved 97-2003 .xls file with the original formatting it had before it was merged?