Index: trunk/MagicSoft/Mars/mfileio/MReadMarsFile.cc
===================================================================
--- trunk/MagicSoft/Mars/mfileio/MReadMarsFile.cc	(revision 9195)
+++ trunk/MagicSoft/Mars/mfileio/MReadMarsFile.cc	(revision 9219)
@@ -201,5 +201,5 @@
     if (!rawheader->IsValid())
     {
-        *fLog << warn << "WARNING - The run header read from the file is invalid." << endl;
+        *fLog << warn << "WARNING - The run header (MRawRunHeader) read from the file returns not IsValid()." << endl;
         *fLog << "          Please check if the file contents are ok." << endl;
         rawheader->Print("header");
Index: trunk/MagicSoft/Mars/mfileio/MWriteRootFile.cc
===================================================================
--- trunk/MagicSoft/Mars/mfileio/MWriteRootFile.cc	(revision 9195)
+++ trunk/MagicSoft/Mars/mfileio/MWriteRootFile.cc	(revision 9219)
@@ -122,5 +122,5 @@
     }
 
-    if (!file)
+    if (!file || TString(name)=="/dev/null")
     {
         file = new TFile(name, option, title, comp);
@@ -760,4 +760,5 @@
     {
         *fLog << err << "ERROR - MWriteRootFile::ChangeFile... something went terribly wrong!" << endl;
+        *fLog <<        "        fname: " << fname << endl;
         *fLog <<        "        Please start debugging!" << endl;
         return kFALSE;