In which language are you running LR?
English (UK), thanks.
F7 does nothing, F8 launches iTunes.
Somehow, your F7 and F8 keys are assigned to be global keys that override the Lightroom assignments of these keys. You need to find out where these are assigned in your MAC setup, and eliminate them. As I am not a Mac user, I cannot be more specific.
Such is my dilemma! As I already stated, I checked the system prefs/keyboard/shortcuts, and nothing listed there has F7 or F8 assigned - I don't know where else to look. I guess I need a Mac/Lightroom expert to chime in, but thanks for your input.
For what it's worth ... on Windows, if the shortcut F8 opened iTunes, then you would need to check the properties of iTunes and remove the keyboard shortcut there; and not the system shortcuts. Perhaps it's the same on a Mac.
Some troubleshooting steps:
1. Reboot your computer.
2. Reset LR's preferences: http://www.lightroomforums.net/showthread.php?25197-Resetting-the-lightroom-preferences-f ile-updated . That often fixes things when LR's user interface goes wonky.
3. In LR, what shortcut appears for the menu command Window > Panels > Show Left Module Panels? Does F7 appear, or something else? This is what it looks like on my system:
4. If F7 doesn't appear, go to System Preferences > Shortcuts > App Shortcuts and create a shortcut for "Adobe Lightroom.app", with menu title "Show Left Module Panels", and shortcut key F7:
Does that fix things? If not, try using Ctrl + F7 instead.
Also, view my reply in the Web browser, not in your email program, to see the embedded screenshots.