收到以下错误，我的应用程序崩溃。删除派生数据仍然不成功。
2016-11-16 17:57:33.285311 WCMH[59760:914565] [MC] Reading from private effective user settings.
2016-11-16 17:57:33.285 WCMH[59760:914454] *** Assertion failure in -[KeychainItemWrapper writeToKeychain],
2016-11-16 17:57:33.286574 WCMH[59760:914580] [] nw_host_stats_add_src recv too small, received 24, expected 28
2016-11-16 17:57:33.287290 WCMH[59760:914580] [] nw_host_stats_add_src recv too small, received 24, expected 28
2016-11-16 17:57:33.289270 WCMH[59760:914580] [] nw_host_stats_add_src recv too small, received 24, expected 28
2016-11-16 17:57:33.290745 WCMH[59760:914580] [] nw_host_stats_add_src recv too small, received 24, expected 28
2016-11-16 17:57:33.290 WCMH[59760:914454] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Couldn't add the Keychain Item.'