Introduction
The Excel files are binary compatible and can be easily transfered between both platforms. The version level must be the same or greater. From Excel 5, you can use the item 'Save as' in the 'File' menu to save as an Excel 3 file. Caution, Excel 4 only knows single data sheet.
Otherwise, the result of the transfert is very good. You get the data and formulas. The conversion also works well with accented letters.

Broken links
When you open a main spreadsheet with references to secundary files, Excel asks you if you want to update the links. It happens that you better answer no at this time, as Excel will not really update your links. You should instead use the item 'Links' in the 'Edit' menu when the file is displayed on screen.

Error opening Macintosh Excel files
If you get an error while opening a file and if the Help button brings an help screen saying that Excel can't open files saved by versions older than 1.5, you will have to open the files on the source computer (Version 3 and 5 of Excel can't open these files either) and save the files as SYLK files (the de facto standard of this time). The signature of these files is XLBNXCEL.