Apps will not open, post OS X Mavericks update
I'm having the same issue on two of my machines. None of the core apps will launch (Mac App Store, Maps, Message, Photobooth, etc.).

One solution that worked for me for a short period of time:


If you hold Command+R on restart, it activates the recovery partition from which you can reinstall OS X Mavericks.
Unfortunately the "fix" doesn't last for long and you're either forced to rinse and repeat, or give up entirely.


There doesn't seem to be a genuine fix anywhere online that works for me.