So I accidentally modified a header (CBCentralManager.h) and caused the above error to show when I build. I searched stack overflow for the solution, and found
CBCentralManager.h)
Remove the pcm file
rm "/var/folders/pj/hslm53_51xxd_npfqym5r6z00000gn/C/com.apple.DeveloperTools/5.0-5A1412/Xcode/5.0-5A1412/Xcode/ModuleCache/FUW5IOHP9BIS/CoreBluetooth.pcm"
then
Clean Project( Cmd+Shift+K)
Problem solved