Finale announced the following in June.

http://www.finalemusic.com/blog/restrictions-may-apply/ 

Meanwhile, there are a few third party Scan-to-MusicXML applications that work pretty well.

If you have an older version of SmartScore Lite included with Finale, you can upgrade to SmartScore X2 Pro for $199.

http://www.musitek.com/SSLiteUpgrade.html

The instructions regarding TWAIN drivers are outdated and useless. Use Image Capture on your Mac to create a file that you can export to Finale via MusicXML.

There are other programs that can do this, too, but SmartScore works better with Finale than other apps I have tried. I found the Lite version included with Finale to be fairly useless by comparison and the upgrade $$$ very well spent when I did it a couple of years ago. What is your time worth? In my case, a lot more than a crippled "free (bundled)" version.

If the OP owns an earlier version of Finale (which I suspect is not the case), one can scan in F2014.5 (or earlier) and bring the file into v25 using copy/paste or XML. It is possible to the new and older versions of Finale on one computer.

I have Finale 2014 and it imports .TIF files. I'm very sorry to hear that the latest Finale does not do that and that an additional software will be necessary. I take a 600dpi PDF into a photo editor (I use Photoshop7) save it as .TIF; edit it as necessary to clean it up. save it again.

Open Finale 2014 > File > Import > Tif

drag the tif pages individually to the finale included software window.

and tell the software to import it.

There are a number of techniques to improve the imported Finale 2014 score. You will often find that enough successful measures result to save you time.;

Sometimes the score is too complex or poorly scanned, but it is not a wasted attempt.

?What is the current Finale-recommended converter at this time?

?What converters have users had good results with for current Finale versions?

SmartScore X2 Pro works well and is designed to work with Finale  

Unlike the "lite" version of SmartScore included with Finale, it handles lyrics and expressions. You have a discount available from SmartScore Lite. 

It's hard for me to believe you cannot enter music from a computer file!  It's so obviously something we want to do.  I guess I'm going to have to buy yet another notation software . . . .

Well, hard as it is for you to believe, that's the case. Many of us don't like it.

As for finding another notation program that allows direct scanning, there's Sibelius and ... nope, just Sibelius, I think. All the others support importation via MIDI and MusicXML. So, it's Sibelius—their utility is a limited feature tool with an upgrade path to a full-featured version, too, just like SS Lite to SS X2.

OTOH, $199 for SmartScore X2 Pro lets you scan and export MusicXML to any notation program including Finale. There are others out there, some for less money but SS X2 was the best I found for working with Finale and MusicXML 3.0. Unlike the Lite version supplied with Finale 2014.5 and earlier, X2 supports lyrics, more expressions and is much more accurate. I upgraded years ago as I found SS Lite to be a time waster by comparison.

If you have an earlier version of Finale, you can still scan using SmartScore Lite and import into Finale 25.