diff --git a/wetb/hawc2/simulation.py b/wetb/hawc2/simulation.py
index 4da68a9b8835312283f5396d61382753abb05cb4..79b2c198db1058c7f7b72e25f96cbe680e25f411 100755
--- a/wetb/hawc2/simulation.py
+++ b/wetb/hawc2/simulation.py
@@ -460,7 +460,7 @@ class SimulationThread(Thread):
         #    self.process = subprocess.Popen('wine "%s" %s 1> %s 2>&1' % (hawc2exe, htcfile, stdout), stdout=None, stderr=None, shell=True, cwd=modelpath)
 
         if isinstance(hawc2exe, tuple):
-            self.process = subprocess.Popen('%s "%s" %s 1> %s 2>&1' % hawc2exe + (htcfile, stdout), stdout=None, stderr=None, shell=True, cwd=modelpath)
+            self.process = subprocess.Popen('%s "%s" %s 1> %s 2>&1' % (hawc2exe + (htcfile, stdout)), stdout=None, stderr=None, shell=True, cwd=modelpath)
         else:
             self.process = subprocess.Popen('"%s" %s 1> %s 2>&1' % (hawc2exe, htcfile, stdout), stdout=None, stderr=None, shell=True, cwd=modelpath)  #, creationflags=CREATE_NO_WINDOW)