Microsoft Excel Workbooks Link Incorrectly after Internet Transfer

Hi, I have 20 or so excel files that are all linked. When I transfer just some of them via email and back again, the links seem to point to some Temp Internet File instead of the workbook. The filenames have not changed though. I have to then remove the Temp Internet File section of the formulas to get each workbook to link correctly again. Is there a way I can avoid this completely?