Some info:

XL: Error Message: Too Many Different Cell Formats
http://support.microsoft.com/default.aspx?scid=213904

A few people have posted that they could open the file in OpenOffice, then
remove some of the formatting, save it and then excel would open that file ok.

http://www.openoffice.org, a 60-65 meg download or a CD


Brettjg wrote:

I have a workbook (about 1.6MB) that constantly gets the above. When this
happens I save, close and reopen, and then I can continue for a while, until
it happens again. Have moved sheets out of the book, but not much help. I
have had this before, but the file size was about 3MB, and moving the sheets
out and back in seemed to help. The files are heavily formatted but there
must be something I can re-set or..............

When it gets to far gone, Excel will just crash and corrupt the original
file by deleting ALL formatting in the book permanently. I have recently
become very zealous about backups, you'll be surprised to learn.

--

Dave Peterson