Could some of you test the very small attached example? I make use of the current petsc-dev, OpenMPI 1.4.1 and GCC 4.2.4. In this environment, using 4 nodes, I get the following output, which is wrong: [3] BCAST-RESULT: 812855920 [2] BCAST-RESULT: 450385 [1] BCAST-RESULT: 450385 [0] BCAST-RESULT: 450385 The problem occurs only when I run the code on different nodes. When I start mpirun on only one node with four threads or I make use of a four core system, everything is fine. valgrind and Allinea DDT, both say that everything is fine. So I'm really not sure where the problem is. Using PETSc 3.1-p8 there is no problem with this example. Would be quite interesting to know if some of you can reproduce this problem or not. Thanks for any try! Thomas