I wonder if some kind soul can help please?

I have a formula in I4 that reads;
=IF(A12="","",IF(I4="",NOW(),I4))

What I believe used to happen was if I input a number in A12 the current
date was automagically inserted in I4

However now when I input a number in A12 I get an error that states;

Microsoft Excel cannot calculate a formula. Cell references in the formula
refer to the formula's result, creating a circular reference.
Try one of the following;
If you accidentally created the circular reference, click OK. This will
display the circular reference toolbar and help for using it to correct your
formula.
For more information about circular references and how to work with them,
please click Help.
To continue leaving the formula as it is, click Cancel

Sometimes a blue dot appears in I4 but no date...

The spreadsheet is protected but it has always been.

I do not recall altering the spreadsheet so is there any setting within
Excel 2000 that will affect or cause this error?

Maybe my formula is wrong?

--
Thanks & regards,
-pp-