File error when opening some Excel files
 

I depend on Excel for most of my record keeping and daily worksheets for the
class I teach at PREF (DOC). I have a problem from time to time that when I
open certain files I get a message that pops up saying: File error; some
information may have been lost.(paraphrased). Everytime that I get this
message, information is lost. It is always the cells that contain an MRound
formula. I cannot determine a pattern of saving of opening the file that
causes this problem. I have noticed though, that when it gives me that error
with one file using the MRound formula it will happen to others that use that
same formula. I have to manually go into each cell and reenter the formula so
that I can use use the worksheet. Any help you can give me would be greatly
appreciated. Thank you. Neil Rissler