How to automatically refresh formulas?

I have Sheet1 with "formula"
=MySheet!A1
in e.g cell A1.
Because MySheet does not exist in this workbook, I get #REF error.
Later when I add MySheet, the #REF error is still there.
But if I select A1 in Sheet1 and then click somwhere in the formula editor line and press ENTER, then A1 changes to 0 (or existing A1 value in MySheet)

I wonder how to automatically refresh some/all formulas in Sheet1 that reference to MySheet, after MySheet is inserted.

Please, see also attached file.