ios打包失败

上周五我打包就可以成功，且不包错，这周重新打包就一直报错：
/ com.apple.ibtool.errors /
安装包制作目录Pandora/en.lproj/MainStoryboard_iPad.storyboard: error: Encountered an error communicating with Interface Builder Cocoa Touch Tool.
Failure Reason: Interface Builder Cocoa Touch Tool (-1) failed to launch
Recovery Suggestion: Please check Console.app for crash reports for "Interface Builder Cocoa Touch Tool" for further information.
Underlying Errors:
Description: Failed to launch Interface Builder Cocoa Touch Tool via CoreSimulator spawn
Failure Reason: Failed to spawn Interface Builder Cocoa Touch Tool on SimDevice : IBSimDeviceTypeiPad1x (8E5E0CD7-BF5C-4726-9AE0-5F37B3E18052) : state={ Shutdown } deviceType={ SimDeviceType : com.apple.dt.Xcode.IBSimDeviceType.iPad-1x } runtime={ SimRuntime : 9.1 (13B137) - com.apple.CoreSimulator.SimRuntime.iOS-9-1 }
Underlying Errors:
Description: The operation couldn’t be completed. Resource temporarily unavailable
Failure Reason: Resource temporarily unavailable

这是怎么回事呀？