I have the following error:
Command /usr/bin/codesign failed with exit code 1
Here is what I already did for trying to fix this:
One solution more works with me, If you installed two versions of XCode and you install the second without uninstalling the first in the same directory (/Developer/), you did it wrong. So the solution that works for me was:
1 - Uninstall the current Xcode version with the command sudo /Developer/Library/uninstall-devtools --mode=all.
2 - Install the first Xcode version you had first.
3 - Again sudo /Developer/Library/uninstall-devtools --mode=all.
4 - Then, all is clean and you are able to install the version you want.
More things: maybe you need to restart the computer after install the Xcode or even (in some cases) install two times the Xcode.
I hope I works it take me a lot of time to know that, good luck!!!