Xcode doesn't start
Solution 1:
-
Delete all files at
~/Library/Preferences/com.apple.dt.* -
Manually install Developer Tools from Terminal by running
xcode-select --install -
Reinstall "XcodeSystemResources.pkg" from contents of Xcode.app itself
/Applications/Xcode.app/Contents/Resources/Packages/XcodeSystemResources.pkg
Finally Xcode 9.0.1 (9A1004) worked perfectly.