diff --git a/regtest/basic/rt1/bck.0.der2.reference b/regtest/basic/rt1/bck.0.der2.reference
new file mode 100644
index 0000000000000000000000000000000000000000..c7900cb654c6710b7753144beb12fe8d48a6e0c1
--- /dev/null
+++ b/regtest/basic/rt1/bck.0.der2.reference
@@ -0,0 +1 @@
+fake file just to test backup
diff --git a/regtest/basic/rt1/der2 b/regtest/basic/rt1/der2
new file mode 100644
index 0000000000000000000000000000000000000000..c7900cb654c6710b7753144beb12fe8d48a6e0c1
--- /dev/null
+++ b/regtest/basic/rt1/der2
@@ -0,0 +1 @@
+fake file just to test backup
diff --git a/regtest/basic/rt18/bck.0.projections.reference b/regtest/basic/rt18/bck.0.projections.reference
new file mode 100644
index 0000000000000000000000000000000000000000..c7900cb654c6710b7753144beb12fe8d48a6e0c1
--- /dev/null
+++ b/regtest/basic/rt18/bck.0.projections.reference
@@ -0,0 +1 @@
+fake file just to test backup
diff --git a/regtest/basic/rt18/projections b/regtest/basic/rt18/projections
new file mode 100644
index 0000000000000000000000000000000000000000..c7900cb654c6710b7753144beb12fe8d48a6e0c1
--- /dev/null
+++ b/regtest/basic/rt18/projections
@@ -0,0 +1 @@
+fake file just to test backup
diff --git a/regtest/basic/rt8/bck.0.ff.reference b/regtest/basic/rt8/bck.0.ff.reference
new file mode 100644
index 0000000000000000000000000000000000000000..c7900cb654c6710b7753144beb12fe8d48a6e0c1
--- /dev/null
+++ b/regtest/basic/rt8/bck.0.ff.reference
@@ -0,0 +1 @@
+fake file just to test backup
diff --git a/regtest/basic/rt8/ff b/regtest/basic/rt8/ff
new file mode 100644
index 0000000000000000000000000000000000000000..c7900cb654c6710b7753144beb12fe8d48a6e0c1
--- /dev/null
+++ b/regtest/basic/rt8/ff
@@ -0,0 +1 @@
+fake file just to test backup
diff --git a/src/bias/MetaD.cpp b/src/bias/MetaD.cpp
index a0a13bcd34899a58da4d049677cd45039f1ee141..01ae2c74aa07d8f0b0344ff17faf3b84c5349138 100644
--- a/src/bias/MetaD.cpp
+++ b/src/bias/MetaD.cpp
@@ -475,8 +475,7 @@ isFirstStep(true)
 
 // open hills file for writing
   hillsOfile_.link(*this);
-  if(plumed.getRestart()) hillsOfile_.open(ifilesnames[mw_id_],"aw");
-  else hillsOfile_.open(ifilesnames[mw_id_]);
+  hillsOfile_.open(ifilesnames[mw_id_]);
   if(fmt.length()>0) hillsOfile_.fmtField(fmt);
   hillsOfile_.addConstantField("multivariate");
   hillsOfile_.setHeavyFlush();
diff --git a/src/generic/DumpAtoms.cpp b/src/generic/DumpAtoms.cpp
index e6929f85d0c81ebc388be58e4121fc23818b477f..48bb7a0b2866006ff103e6bcdd4abf1ac5689a42 100644
--- a/src/generic/DumpAtoms.cpp
+++ b/src/generic/DumpAtoms.cpp
@@ -153,7 +153,7 @@ DumpAtoms::DumpAtoms(const ActionOptions&ao):
 
   checkRead();
   of.link(*this);
-  of.open(file.c_str());
+  of.open(file);
   log.printf("  printing the following atoms in %s :", unitname.c_str() );
   for(unsigned i=0;i<atoms.size();++i) log.printf(" %d",atoms[i].serial() );
   log.printf("\n");
diff --git a/src/generic/DumpDerivatives.cpp b/src/generic/DumpDerivatives.cpp
index 72e73e8a8a6a4a54048983cf1ff31278b073830d..b4a0f52a217edb586305ab76f0b0b8e2d7e6e3fb 100644
--- a/src/generic/DumpDerivatives.cpp
+++ b/src/generic/DumpDerivatives.cpp
@@ -91,7 +91,7 @@ fmt("%15.10f")
   parse("FMT",fmt);
   fmt=" "+fmt;
   of.link(*this);
-  of.open(file,"wa");
+  of.open(file);
   log.printf("  on file %s\n",file.c_str());
   log.printf("  with format %s\n",fmt.c_str());
   unsigned nargs=getNumberOfArguments();
diff --git a/src/generic/DumpForces.cpp b/src/generic/DumpForces.cpp
index 696af62d76e5191968e9233c7dba9620791b1704..4dfdfd56656198a3633e223da4f14da86d6e21e4 100644
--- a/src/generic/DumpForces.cpp
+++ b/src/generic/DumpForces.cpp
@@ -87,7 +87,7 @@ ActionWithArguments(ao)
   parse("FILE",file);
   if( file.length()==0 ) error("name of file was not specified");
   of.link(*this);
-  of.open(file,"wa");
+  of.open(file);
   log.printf("  on file %s\n",file.c_str());
   if( getNumberOfArguments()==0 ) error("no arguments have been specified");
   checkRead();
diff --git a/src/generic/DumpProjections.cpp b/src/generic/DumpProjections.cpp
index 3c3b8968fcc30a44b167853c07a19e1772711efa..6f622e1f754b9be20a72a6e7506ff085cbb53f7e 100644
--- a/src/generic/DumpProjections.cpp
+++ b/src/generic/DumpProjections.cpp
@@ -75,7 +75,7 @@ fmt("%15.10f")
   if( file.length()==0 ) error("filename not specified");
   parse("FMT",fmt);
   fmt=" "+fmt;
-  of.open(file.c_str(),"wa");
+  of.open(file);
   log.printf("  on file %s\n",file.c_str());
   log.printf("  with format %s\n",fmt.c_str());
   checkRead();
diff --git a/src/generic/Print.cpp b/src/generic/Print.cpp
index 28484a84f5b0de5a5f364f7fbba10ecdbe010dd1..9fec9e43eb7347754280343945d6dc3a99257111 100644
--- a/src/generic/Print.cpp
+++ b/src/generic/Print.cpp
@@ -101,7 +101,7 @@ rotate(0)
   ofile.link(*this);
   parse("FILE",file);
   if(file.length()>0){
-    ofile.open(file.c_str());
+    ofile.open(file);
     log.printf("  on file %s\n",file.c_str());
   } else {
     log.printf("  on plumed log file\n");