Don't we all hate when we plugin our iOS7 devices to our trusted Mac and suddenly the mobile device asks us "Do you want to trust this computer"? And we go, of course! We have been syncing together for a while, what about this sudden hostility?
The past three times this happened, I had to resort to rebooting the Mac several times and resetting the iOS device because someone on some blog said that helped, and re-installing the latest version of iTunes.
The resetting of the iOS device was the worst, because all my settings (WLAN, etc) got lost every time. So when I plugged in my iPhone this morning and got greeted by the chirpy "Do you want to trust this computer?" I snapped.
Looking in the Console system log, I saw this everytime I started iTunes
12/15/2013 15 Dec 11:07:05 /Applications/iTunes.app/Contents/MacOS/iTunes tid:1403 - Failed to create mux listener
12/15/2013 15 Dec 11:07:05 /Applications/iTunes.app/Contents/MacOS/iTunes Failed to register for device notification events and start runloop
12/15/2013 15 Dec 11:07:05 /Applications/iTunes.app/Contents/MacOS/iTunes Failed to initialize MobileRestore, can't perform registration right now.
12/15/2013 15 Dec 11:07:06 [0x0-0x9b09b0].com.apple.iTunes Returning 0x0. Advertising wake service for libraryIdentifier "FB6220DD85A8380D".
12/15/2013 15 Dec 11:07:06 iTunes _SubscribeForMuxNotifications (thread 0xb083d000): USBMuxListenerCreate: Connection refused
The following fixed it for me
sudo launchctl unload /System/Library/LaunchDaemons/com.apple.usbmuxd.plist
sudo launchctl load /System/Library/LaunchDaemons/com.apple.usbmuxd.plist
I am still running 10.6.8 because in its infinite wisdom Apple decided that my Mac Pro 1,1 is no longer supported so I can't (easily) update to Lion or Mountain Lion.