diff -up src/sage/numerical/backends/coin_backend.pyx.orig src/sage/numerical/backends/coin_backend.pyx
--- src/sage/numerical/backends/coin_backend.pyx.orig	2018-12-22 16:37:09.000000000 -0700
+++ src/sage/numerical/backends/coin_backend.pyx	2019-01-16 09:45:52.386577640 -0700
@@ -780,8 +780,8 @@ cdef class CoinBackend(GenericBackend):
         model.setLogLevel(old_logLevel)
 
         # multithreading
-        import multiprocessing
-        model.setNumberThreads(ncpus())
+        #import multiprocessing
+        #model.setNumberThreads(ncpus())
 
         model.branchAndBound()