final cut pro sound effects

I know you said you downloaded the effects but have they actually arrived on your computer?

Check that they are in the right place by opening your Mac HD and selecting Library>Audio>Apple Loops>Apple>Final Cut Pro Sound Effects as shown in the screenshot below.

When you open the Final Cut Pro Sound Effects folder you should find all the effects.

If they are not there it means the download has failed.

Have you left it long enough after pressing the Sound Effects button?

I used to have a great many extra effects and when I pressed the button nothing appeared for at least 30 seconds.

Before I discovered what was happening I used to think they weren't working and would switch back to something else.

Interesting. On a system with no FCP installation I can't get additional content from the trial version. I get what the OP saw, everything up to date. Wondering if it might be location specific issue.

Have you actually downloaded the Sound Effects?

In the FCP menubar select Download Additional Content.

Try deleting the preferences. . . . hold the option and command keys down as you launch FCP until a window appears. Click on Delete.

Not Library/Apple. Library/Audio/Apple Loops

In FCP go to File>Download Additional Content and tell us exactly what happens. You should be transferred to System Settings.

Are you using the trial version?

Trial version lets you download the additional content.

Apple may not allow additional content any longer with the trial version? They used to. That may have changed.