After updating to Mavericks and making sure I got the latest updates of Xcode installed as well, Xcode suddenly fails to launch apps on the device.
It installs the app on my iPhone but then before running it, throws this error:
Process launch failed: Failed to get the task for process 216
This is how the Code Signing settings look like since the update:

Also checked Scheme and it runs in Debug configuration.
Is this a known issue with Mavericks? How to fix it?
]
Figured it out. My Developer Certificate was marked as "Expired" in Keychain (search Spotlight for "Keychain", then click on the "user" tab on the left). I deleted it, then went to Xcode > Preferences > Accounts, selected my ID and clicked on "View Details", then clicked the Update icon at the bottom left. Xcode re-installed the renewed certificate. Then I went to Build Settings and manually set the Debug configuration to use the Developer certificate Xcode just reinstalled for me.