it seems that Excel file transfer between a Mac and a PC, (and vice versa), is possible, as long as you are transferring between compatible Excel versions. I saw this at a web site, (link below);
"Save your Excel file in a format compatible with the other person's version of Excel. Excel files are compatible as long as they are the same version or greater. All Excel file types are backward compatible with older versions of Excel".
Now the problem is, is your PC 2010 version of Excel the same version as the receiver's Mac version of Excel 2008. I don't know.
So, try this. Ask the receiver to send you a bog standard Excel file from her machine in the normal file format she uses. EG, if she sends you a file in .xls format, and it opens properly in your version if Excel, then you know that she should be able to receive your own .xls excel file version.
It might need a bit of experimenting to get it right.
Shame its not Word. The answer there would be Rich Text Format, .rtf .
I am trying to determine whether there is a known compatibility/format loss issue between files (Excel specifically) created Microsoft office for 2010 to be opened in Office 2008 for Mac. I have to regularly send documents I've created in 2010 to a Mac user who is running 2008 on her Mac, and it seems as if she always loses the formatting that I save it in.
I realize there are a lot of solutions to this problem (I.E... sending her the documents in a PDF form so loss of format is not an option, or faxing them to her OR she could fix the formatting - if she knew how). Unfortunately, I really am just trying to determine the possibility of the format loss. I know anything is possible, but is it an established pattern and regularly reported complaint/problem?