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	2017-11-08 08:23:51.731208448 -0500
+++ src/sage/numerical/backends/coin_backend.pyx	2017-11-08 08:24:02.347208854 -0500
@@ -759,8 +759,8 @@ cdef class CoinBackend(GenericBackend):
         model.setLogLevel(old_logLevel)
 
         # multithreading
-        import multiprocessing
-        model.setNumberThreads(multiprocessing.cpu_count())
+        #import multiprocessing
+        #model.setNumberThreads(multiprocessing.cpu_count())
 
         model.branchAndBound()