Breakpoints are not working with Xcode 6

There are many reasons for this.

Please check this:
http://stackoverflow.com/questions/64790/why-arent-my-breakpoints-working

In my case what worked for me is:
Click on the Xcode project-> Build Settings ->Build Options -> set "Debug Information Format" as "DWARF with dSYM File".

This is in Xcode 6.1