Need more info.

1. What version of Finale are you using?
2. What computer operating system (and what version)?
3. What Human Playback setting are you using?
4. Did you start playback at the start of the file?
5. Where in the file (start, middle, end) do you apply the pizz?

Presumably you are using the pizz from the expressions menu.

Hello J Adrian,

1) Finale 2012

2) MacOS X 10.7.5

3) Standard

4) Yes

5) Start, middle and end (Small sections)

I am but it does not do it.

I chequed my old files and they did but as of yesterday not even the old files are doing it. I have been assigning Violins KS and, subsequently like that ,all the strings and only the Basses and cellos are doing it.

So far, I am stumped.

If no one else has a solution, you might try the "Submit a request" link at the top of the page to send your file to MakeMusic Support. That assumes they are still looking at material from Finale 2012. It's worth a try.

I'm guessing you already tried restarting Finale and rebooting your computer.