Can you find the character in another font?

Maybe his copy of the font was corrupred in transmission. Do you have something like PopChars?

There are up and down arrows in the Lucida Grande font. Would they work, instead?

The Lucida font family is not one of the fonts that Finale normally uses. Only Lucida Grande is included in the Mac OS. If you do not see Lucida Bright in Font Book, you will not see it in a Finale document.

Lucida Bright can be purchased from Microsoft and is included in a number of their products.

If Lucida Bright is a 'hidden' font, found only inside an application, it must be installed before Finale or any other app can access it. This is easy — open the font and click on Install. You will get warnings—all notation and symbol fonts generate them. Check the boxes and click through the warnings to install. It will now show up in Font Book.app.

I have it on my system — probably came with Office. I don't recall if it installed with Office or if it was a hidden font and I had to install it manually (I always do that with hidden fonts as I find them).

I installed Lucida Bright Math Symbol as you suggested - just double-clicking on the font itself - and clicked "install." As you said, it showed up in Font Book, but still with the same "yellow light" warning. I restarted the computer and opened Finale - still the same problem.

When I access the Expression Designer and look at one of the expressions in question, in the font drop-down menu, Lucida Bright Math Symbol is selected, and of course appears in the long list of fonts. I tried selecting a different font and then coming back to Lucida Bright Math Symbol, but this did not help either.

Any other ideas?

Can you use the symbol from Lucida Grande? do you have a picture of what the character looks like?

Well, my client really likes this particular font for the arrow, so I'm trying to satisfy him if at all possible.

Do you know, what is the keyboard combination for typing and upward arrow and a downward arrow? I'm having trouble finding that information. I'd like to try some arrows in other fonts. Thank you.

Buy PopChar. It's the best $30 you can spend. You don't need to know the keystrokes; you just click on the character.

Yes, I know there are other font viewers, but I have not found anything as useful.

http://www.ergonis.com/products/popcharx/ 

Go back to your original error. I don't know where you obtained your copy of Lucida Bright but it does not have the required snft required tables. This is common with many fonts available on the free font download sites.

https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6.html

You are best off acquiring the font from Microsoft or its developer.

https://www.microsoft.com/typography/fonts/font.aspx?FMID=721

You can also have your customer use a different font. 

If you have Office 2011 or later, you probably have the correct version but it may be in the Applications folder. You will need to remove the installed version in Font Book and install the Microsoft version as I mentioned earlier.

With the Finale file open have you tried using Data Check, Font tools - compare file fonts with System fonts?

If it flags this font, then that will confirm that Finale is not seeing it. In the font list in any tool it will appear italicised - meaning that it is used in the file but isn't on your system.

I have a couple of fonts that worked fine in earlier versions of Finale, but not in the new 64 bit version. I have had to buy new versions of New Century Schoolbook because the one I've used since 1989 no longer works.