Failing snapshots in XCode

Did it ever happened to you that the XCode "File > Make Snaphot" fails miserably with a Cannot-change-permissions-somewhere-down-over-/tmp/XY!$%^ ?

Well if so check the permissions of your project file, they must be writable by the owner only. To fix the problem launch a terminal, go in the project folder and use the

chmod -Rv g-w,o-w *

command. Of course double check you really are in the project folder and you really don't need those writing permissions in place.