diff --git a/src/external/MuSRFitGUI/MSR.pm b/src/external/MuSRFitGUI/MSR.pm
index b496f419..1c7e5ea3 100755
--- a/src/external/MuSRFitGUI/MSR.pm
+++ b/src/external/MuSRFitGUI/MSR.pm
@@ -17,7 +17,7 @@ my %DATADIRS = (
 my %BeamLines = ( "LEM", "MUE4", "LEM (PPC)", "MUE4", "GPS", "PIM3", "LTF", "PIM3", "Dolly", "PIE1", "GPD", "PIE1" );
 
 my %Def_Format =
-  ( "LEM", "ROOT-NPP", "LEM (PPC)", "ROOT-PPC", "GPS", "PSI-BIN", "LTF", "PSI-BIN", "Dolly", "PSI-BIN" , "GPD", "PSI-BIN");
+  ( "LEM", "MUSR-ROOT", "LEM (PPC)", "ROOT-PPC", "GPS", "PSI-BIN", "LTF", "PSI-BIN", "Dolly", "PSI-BIN" , "GPD", "PSI-BIN");
 
 # Additional information to extract run properties from database
 # For LEM use summary files
@@ -1717,7 +1717,7 @@ sub RUNFileNameAuto {
     my $RUN_Line=$EMPTY;
 # if BeamLine is empty assume manual name
     if ($BeamLine eq $EMPTY) {
-	my %EXTs = ("root","ROOT-NPP",
+	my %EXTs = ("root","MUSR-ROOT",
 		    "bin","PSI-BIN",
 		    "msr","MUD");