press + alt + b to see all breakpoints.
Select the breakpoint you want to delete and click "Delete."
if the problem persists then follow these steps
Included in the "Assembly Settings" as part of the target project change the "Optimization Level" for "Debug" to "No".
OR
In xCode4:
The name of your project → Change the scheme Information tab (in the launch configuration) Set the configuration to Debug, Debugger to LLDB (formerly GDB) Run the project.
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