Bob wrote:

Thanks Bob.

Interestingly, that was the first thing I tried, but it didn't work for me.
It seems some pilot error crept in.

I didn't type the leading '=' sign because the Conditional Formatting
dialogue box seemed to put that in automatically.  I just entered the text
in quotation marks.

I've now spotted that not only is the '=' sign put in automatically, but so
are the quotation marks, so my entered text actually ended up as:

 =""Warning - value is outside of set limits""

Which is why it didn't work.

It works now  :-)

Another thing...

The actual 'Equal to' text line I have to match is much longer than the
example I gave in this post.  It exceeds the width of the text box field,
which is why I was hoping I could use a much shorter keyword search instead.

I can't find a way of navigating through the text line to check for errors.
Using the mouse cursor only works on text that is visible within the text
box field.  Using the arrow keys to scroll to text that extends beyond the
text box field doesn't work (for me).  Instead the arrow key inserts an
adjacent cell reference (such as +$B$52) into the text line.

So, what am I missing?  How do I scroll right to bring hidden text into
view?  I'm using Excel 2002 SP3.

I have just discovered that clicking on the icon to the right of the text
field extends the field to the full width of the dialogue box, but the
scroll problem persists if the text line is still longer than the extended
text box field.

Thanks