I file a bug to Apple through their bug report. Now they ask me send log.
How to collect xcode log? I have system log and console log ready.
I do not believe Xcode writes a dedicated log file. However, the Console app should have everything you need (you'd need to filter by PROCESS|Xcode to see only Xcode entries).
Alternatively, starting Xcode from the terminal window (via /Applications/Xcode-beta.app/Contents/MacOS/Xcode
) should produce only Xcode logs.
Please see my other answer for more details.