It is unreadable not corrupt. The error message says "Excel found unreadable content in "filename.xls'. Do you want to recover the contents of this workbook?" Recovering strips out all formatting and macro's, but the data is still there. I've tried enabling and disabling the marco's when opening the file and they don't seem to have any effect.

The path with the server name is 45 characters including the "\"'s and the file nae has 27 characters including the ".xls"

I've tried the same file in other folders and found the same problem. Some with shorter paths and some with longer paths names. I've tried Open and Repair on the initial file before it becomes unreadable, but nothing seems to make a difference except the path.