Also it seems to be happen randomly.
so.its not every time when devfee mining starts?
please could you put --logfile log.txt in .bat so we can get more info
8-04-15 22:21:20] Switching back to user pool in 9991 ticks
[2018-04-15 22:21:20] Switching back to user pool in 9990 ticks
[2018-04-15 22:21:21] Switching back to user pool in 9989 ticks
[2018-04-15 22:21:21] Switching back to user pool in 9988 ticks
[2018-04-15 22:21:22] Switching back to user pool in 9987 ticks
[2018-04-15 22:21:22] Switching back to user pool in 9986 ticks
[2018-04-15 22:21:23] Switching back to user pool in 9985 ticks
[2018-04-15 22:21:24] Switching back to user pool in 9984 ticks
[2018-04-15 22:21:24] Switching back to user pool in 9983 ticks
[2018-04-15 22:21:25] Switching back to user pool in 9982 ticks
[2018-04-15 22:21:25] Switching back to user pool in 9981 ticks
[2018-04-15 22:21:26] Switching back to user pool in 9980 ticks
[2018-04-15 22:21:26] Switching back to user pool in 9979 ticks
[2018-04-15 22:21:27] Switching back to user pool in 9978 ticks
[2018-04-15 22:21:27] Switching back to user pool in 9977 ticks
[2018-04-15 22:21:28] Switching back to user pool in 9976 ticks
[2018-04-15 22:21:28] Switching back to user pool in 9975 ticks
[2018-04-15 22:21:29] Switching back to user pool in 9974 ticks
[2018-04-15 22:21:29] Switching back to user pool in 9973 ticks
[2018-04-15 22:21:30] Switching back to user pool in 9972 ticks
[2018-04-15 22:21:30] Switching back to user pool in 9971 ticks
[2018-04-15 22:21:31] Switching back to user pool in 9970 ticks
[2018-04-15 22:21:31] Switching back to user pool in 9969 ticks
[2018-04-15 22:21:32] Switching back to user pool in 9968 ticks
[2018-04-15 22:21:32] Switching back to user pool in 9967 ticks
[2018-04-15 22:21:33] Switching back to user pool in 9966 ticks
[2018-04-15 22:21:33] Switching back to user pool in 9965 ticks
[2018-04-15 22:21:34] Switching back to user pool in 9964 ticks
[2018-04-15 22:21:34] Switching back to user pool in 9963 ticks
[2018-04-15 22:21:35] Switching back to user pool in 9962 ticks
[2018-04-15 22:21:35] Switching back to user pool in 9961 ticks
[2018-04-15 22:21:36] Switching back to user pool in 9960 ticks
[2018-04-15 22:21:36] Switching back to user pool in 9959 ticks
[2018-04-15 22:21:37] Switching back to user pool in 9958 ticks
[2018-04-15 22:21:37] Switching back to user pool in 9957 ticks
[2018-04-15 22:21:38] Switching back to user pool in 9956 ticks
[2018-04-15 22:21:38] Switching back to user pool in 9955 ticks
[2018-04-15 22:21:39] Switching back to user pool in 9954 ticks
[2018-04-15 22:21:39] Switching back to user pool in 9953 ticks
[2018-04-15 22:21:40] Switching back to user pool in 9952 ticks
[2018-04-15 22:21:40] Switching back to user pool in 9951 ticks
[2018-04-15 22:21:41] Switching back to user pool in 9950 ticks
[2018-04-15 22:21:41] Switching back to user pool in 9949 ticks
[2018-04-15 22:21:42] Switching back to user pool in 9948 ticks
[2018-04-15 22:21:42] Switching back to user pool in 9947 ticks
[2018-04-15 22:21:43] Switching back to user pool in 9946 ticks
[2018-04-15 22:21:43] Switching back to user pool in 9945 ticks
[2018-04-15 22:21:44] Switching back to user pool in 9944 ticks
[2018-04-15 22:21:44] Switching back to user pool in 9943 ticks
[2018-04-15 22:21:45] Switching back to user pool in 9942 ticks
[2018-04-15 22:21:45] Switching back to user pool in 9941 ticks
[2018-04-15 22:21:46] Switching back to user pool in 9940 ticks
[2018-04-15 22:21:46] Switching back to user pool in 9939 ticks
[2018-04-15 22:21:47] Switching back to user pool in 9938 ticks
[2018-04-15 22:21:47] Switching back to user pool in 9937 ticks
[2018-04-15 22:21:48] Switching back to user pool in 9936 ticks
[2018-04-15 22:21:48] Switching back to user pool in 9935 ticks
[2018-04-15 22:21:49] Switching back to user pool in 9934 ticks
[2018-04-15 22:21:49] Switching back to user pool in 9933 ticks
[2018-04-15 22:21:50] Switching back to user pool in 9932 ticks
[2018-04-15 22:21:50] Switching back to user pool in 9931 ticks
[2018-04-15 22:21:51] Switching back to user pool in 9930 ticks
[2018-04-15 22:21:51] Switching back to user pool in 9929 ticks
[2018-04-15 22:21:52] Switching back to user pool in 9928 ticks
[2018-04-15 22:21:52] Switching back to user pool in 9927 ticks
[2018-04-15 22:21:53] Switching back to user pool in 9926 ticks
[2018-04-15 22:21:53] Switching back to user pool in 9925 ticks
[2018-04-15 22:21:54] Switching back to user pool in 9924 ticks
[2018-04-15 22:21:54] Switching back to user pool in 9923 ticks
[2018-04-15 22:21:55] Switching back to user pool in 9922 ticks
[2018-04-15 22:21:55] Switching back to user pool in 9921 ticks
[2018-04-15 22:21:56] Switching back to user pool in 9920 ticks
[2018-04-15 22:21:56] Switching back to user pool in 9919 ticks
[2018-04-15 22:21:57] Switching back to user pool in 9918 ticks
[2018-04-15 22:21:57] Switching back to user pool in 9917 ticks
[2018-04-15 22:21:58] Switching back to user pool in 9916 ticks
[2018-04-15 22:21:59] Switching back to user pool in 9915 ticks
[2018-04-15 22:21:59] Switching back to user pool in 9914 ticks
[2018-04-15 22:22:00] Switching back to user pool in 9913 ticks
[2018-04-15 22:22:00] Switching back to user pool in 9912 ticks
[2018-04-15 22:22:01] Switching back to user pool in 9911 ticks
[2018-04-15 22:22:01] Switching back to user pool in 9910 ticks
[2018-04-15 22:22:02] Switching back to user pool in 9909 ticks
[2018-04-15 22:22:02] Switching back to user pool in 9908 ticks
[2018-04-15 22:22:03] Switching back to user pool in 9907 ticks
[2018-04-15 22:22:03] Switching back to user pool in 9906 ticks
[2018-04-15 22:22:04] Switching back to user pool in 9905 ticks
[2018-04-15 22:22:04] Switching back to user pool in 9904 ticks
[2018-04-15 22:22:05] Switching back to user pool in 9903 ticks
[2018-04-15 22:22:05] Switching back to user pool in 9902 ticks
[2018-04-15 22:22:06] Switching back to user pool in 9901 ticks
[2018-04-15 22:22:06] Switching back to user pool in 9900 ticks
[2018-04-15 22:22:07] Switching back to user pool in 9899 ticks
[2018-04-15 22:22:07] Switching back to user pool in 9898 ticks
[2018-04-15 22:22:08] Switching back to user pool in 9897 ticks
[2018-04-15 22:22:08] Switching back to user pool in 9896 ticks
[2018-04-15 22:22:09] Switching back to user pool in 9895 ticks
[2018-04-15 22:22:09] Switching back to user pool in 9894 ticks
[2018-04-15 22:22:10] Switching back to user pool in 9893 ticks
[2018-04-15 22:22:10] Switching back to user pool in 9892 ticks
[2018-04-15 22:22:11] Switching back to user pool in 9891 ticks
[2018-04-15 22:22:11] Switching back to user pool in 9890 ticks
[2018-04-15 22:22:12] Switching back to user pool in 9889 ticks
[2018-04-15 22:22:12] Switching back to user pool in 9888 ticks
[2018-04-15 22:22:13] Switching back to user pool in 9887 ticks
[2018-04-15 22:22:13] Switching back to user pool in 9886 ticks
[2018-04-15 22:22:14] Switching back to user pool in 9885 ticks
[2018-04-15 22:22:14] Switching back to user pool in 9884 ticks
[2018-04-15 22:22:15] Switching back to user pool in 9883 ticks
[2018-04-15 22:22:15] Switching back to user pool in 9882 ticks
[2018-04-15 22:22:16] Switching back to user pool in 9881 ticks
[2018-04-15 22:22:16] Switching back to user pool in 9880 ticks
[2018-04-15 22:22:17] Switching back to user pool in 9879 ticks
[2018-04-15 22:22:17] Switching back to user pool in 9878 ticks
[2018-04-15 22:22:18] Switching back to user pool in 9877 ticks
[2018-04-15 22:22:18] Switching back to user pool in 9876 ticks
[2018-04-15 22:22:19] Switching back to user pool in 9875 ticks
[2018-04-15 22:22:19] Switching back to user pool in 9874 ticks
[2018-04-15 22:22:20] Switching back to user pool in 9873 ticks
[2018-04-15 22:22:20] Switching back to user pool in 9872 ticks
[2018-04-15 22:22:21] Switching back to user pool in 9871 ticks
[2018-04-15 22:22:21] Switching back to user pool in 9870 ticks
[2018-04-15 22:22:22] Switching back to user pool in 9869 ticks
[2018-04-15 22:22:22] Switching back to user pool in 9868 ticks
[2018-04-15 22:22:23] Switching back to user pool in 9867 ticks
[2018-04-15 22:22:23] Switching back to user pool in 9866 ticks
[2018-04-15 22:22:24] Switching back to user pool in 9865 ticks