diff --git a/moorpy/system.py b/moorpy/system.py
index a358524..f7a7c59 100644
--- a/moorpy/system.py
+++ b/moorpy/system.py
@@ -124,9 +124,9 @@ def __init__(self, file="", dirname="", rootname="", depth=0, rho=1025, g=9.81,
         if self.qs==0:  # if the mooring system is desired to be used as a portrayal of MoorDyn data
             # Load main mooring file
             if Fortran:
-                self.loadData(dirname, rootname, sep='.MD.')
+                self.loadData(dirname, rootname, sep='.MD')
             else:
-                self.loadData(dirname, rootname, sep='_')
+                self.loadData(dirname, rootname, sep='')
             
             if len(file)==0 or len(rootname)==0:
                 raise ValueError("The MoorDyn input file name and the root name of the MoorDyn output files (e.g. the .fst file name without extension) need to be given.")
@@ -3450,7 +3450,7 @@ def loadData(self, dirname, rootname, sep='.MD.'):
         '''
         
         # Temporarily storing all data in main output file in system.data ..... probably will want to change this at some point
-        if path.exists(dirname+rootname+'.MD.out'):
+        if path.exists(dirname+rootname+sep+'.out'):
         
             self.data, self.ch, self.channels, self.units = read_mooring_file(dirname+rootname+sep, "out") # remember number starts on 1 rather than 0