It might be due to Advance Filter... Have you tried to clear the filter?

If it does not work then try to change the row hight to a fixed value.

As a last resort, as you said, loop throught the rows and clear the hidden
setting...
"Bob Flanagan" wrote:

I have a number of rows in the middle of my data that are hidden and whose
height is zero. I have selected the entire sheet and issued both manual
commands (Format, Row, Unhide or autofit) and the row stays hidden. I have
done the same with vb code:

ActiveSheet.UsedRange.EntireRow.Hidden = False
ActiveSheet.UsedRange.EntireRow.AutoFit

and the rows stay hidden. The only way I have found to make a row visible
is to specifically change the row's hidden property. For example:

Rows(663).Hidden = False

Obviously I can rotate through all the rows, but that is very inefficient.
The worksheet is not protected. I can delete the rows any time I want.

Any idea why the first two commands above do not work? Using Excel 2003.

Bob