Click the cell that displays the error, click the button that appears , and
then click Trace Error if it appears.
You can find possible solutions there after.
This basically happens when you paste cells over cells referred to by other
formulas, or using a link to a program that is not running, linking to a
dynamic data exchange or running a macro that enter a function that returns #
REF!
in case you do require those cells to be referred by other formulas you
