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	2015-11-06 10:36:17.498631801 -0200
+++ src/sage/numerical/backends/coin_backend.pyx	2015-11-06 10:36:40.210632670 -0200
@@ -761,8 +761,8 @@ 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()