diff -ur HepMC-2.06.09.orig/src/IO_AsciiParticles.cc HepMC-2.06.09/src/IO_AsciiParticles.cc
--- HepMC-2.06.09.orig/src/IO_AsciiParticles.cc	2010-05-17 17:23:44.000000000 +0200
+++ HepMC-2.06.09/src/IO_AsciiParticles.cc	2015-03-06 17:38:41.860507302 +0100
@@ -156,14 +156,14 @@
 
       xmassi = (*part)->generatedMass();
       if(fabs(xmassi) < 0.0001) xmassi =0.;
-      m_outstream->setf(std::ios::fixed);
+      m_outstream->unsetf(std::ios::floatfield);
       m_outstream->precision(3);
       m_outstream->width(8);
       *m_outstream << xmassi << " ";
       m_outstream->setf(std::ios::scientific,std::ios::floatfield);
       m_outstream->precision(m_precision);
 
-      m_outstream->setf(std::ios::fixed);
+      m_outstream->unsetf(std::ios::floatfield);
       m_outstream->precision(3);
       m_outstream->width(6);
       etai = (*part)->momentum().eta();