Why do some applications in System Preferences say "To use the “xxx” preferences pane, System Preferences must quit and reopen."

Question

When I open my MIDI driver in System Preferences I get the following message:

"To use the “YAMAHA USB-MIDI Control Panel” preferences pane, System Preferences must quit and reopen."

Then when I open a normal thing like "Sharing" "Sound" or "Startup Disk", I get the same prompt. It's as if I'm switching between different modes.

What is going on in the background? Is this to run some compatibility script? Why does the system need to prompt for this?

Answer 1

Some preference panes are 32-bit binaries and some are 64-bits. When System Preferences is in 64-bit mode, to launch a 32-bit preference pane, the app needs to re-launch.

More information is available from Apple or from MacWorld.