You have a cell reference that pointing to itself, that is a big no no. Find
it using the Circular reference tool,
If the Circular Reference toolbar is not displayed, click Customize on the
Tools menu, click the Toolbars tab, and then select the Circular Reference
check box.
On the Circular Reference toolbar, click the first cell in the Navigate
Circular Reference box.
Review the formula in the cell. If you cannot determine whether the cell is
the cause of the circular reference, click the next cell in the Navigate
Circular Reference box.
Note The status bar displays the word "Circular," followed by a reference
to one of the cells contained in the circular reference. If the word
"Circular" appears without a cell reference, the active worksheet does not
contain the circular reference.
Continue to review and correct the circular reference until the status bar
no longer displays the word "Circular."
