I have an Excel file being corrupted by SaveAs. The problem occurs
when I open it from a filesystem folder (local or networked hard disk
in NTFS format, or removable Flash media in FAT format), and SaveAs to
another filesystem (a different local or networked hard disk, or a
different removable Flash media). When I attempt to open the new
file, the displayed error is
"Excel found unreadable content in 'test file 123.xls'. Do you want
to recover the contents of this workbook? If you trust the source of
this workbook, click Yes."

If I continue with the recovery, data and formulas are recovered, but
formatting and macros are lost.

The file is a modest size, 1.6 MB, lots of formulas, no external
links.

This occurs on XP and Vista, on Excel 2003 and 2007.

With 2007, when the SaveAs is to Macro enabled XML format, the
"unreadable content" message occurs, but the recovery seems to be
complete.