Message from debugger: unable to attach error for osx app

Question

I have been building mac app on my mac mini and it always worked well but today i faced this error, searched a lot but no luck.

Message from debugger: unable to attach

What i tried:

• Clear derived data
• Quit Xcode
• Restart machine
• installation directory set to blank and also to /Applications
• Tried Skip Install No / Yes
• Using developer Signing certs
• M using only Developer certificates and not provisioning profile to sign my cocoa app

Xcode 8.2

OSX 10.12.1

Please help :)

Answer 1

This is what fixed it for me, perhaps it will help others but I do realize the question was for 8.2. I had it set to Xcode 9 "New Build System" disabling this and switching to "Standard Build System" in the Project Settings under the File Menu. I had tried all the other things like killing DerivedData, clean build, restarting Xcode. I also verified that my dependent libraries were set correctly. The only thing that worked was disabling new "New Build System"