diff --git a/invesalius/data/imagedata_utils.py b/invesalius/data/imagedata_utils.py
index 19ed2df..0dd210e 100644
--- a/invesalius/data/imagedata_utils.py
+++ b/invesalius/data/imagedata_utils.py
@@ -210,6 +210,13 @@ def ExtractVOI(imagedata,xi,xf,yi,yf,zi,zf):
 
 def CreateImageData(filelist, zspacing):
     message = "Generating multiplanar visualization..."
+    
+    if not const.VTK_WARNING:
+        fow = vtk.vtkFileOutputWindow()
+        fow.SetFileName('vtkoutput.txt')
+        ow = vtk.vtkOutputWindow()
+        ow.SetInstance(fow)
+    
     if not(const.REDUCE_IMAGEDATA_QUALITY):
         update_progress= vtk_utils.ShowProgress(1, dialog_type = "ProgressDialog")
 
diff --git a/invesalius/reader/dicom_reader.py b/invesalius/reader/dicom_reader.py
index 839b7e3..33b26c9 100644
--- a/invesalius/reader/dicom_reader.py
+++ b/invesalius/reader/dicom_reader.py
@@ -118,13 +118,6 @@ def yGetDicomGroups(directory, recursive=True, gui=True):
     yield grouper.GetPatientsGroups()
 
 def GetDicomGroups(directory, recursive=True):
-    
-    if not const.VTK_WARNING:
-        fow = vtk.vtkFileOutputWindow()
-        fow.SetFileName('vtkoutput.txt')
-        ow = vtk.vtkOutputWindow()
-        ow.SetInstance(fow)
-        
     return yGetDicomGroups(directory, recursive, gui=False).next()
 
 
@@ -152,6 +145,12 @@ class ProgressDicomReader:
 
     def GetDicomGroups(self, path, recursive):
         
+        if not const.VTK_WARNING:
+            fow = vtk.vtkFileOutputWindow()
+            fow.SetFileName('vtkoutput.txt')
+            ow = vtk.vtkOutputWindow()
+            ow.SetInstance(fow)
+        
         y = yGetDicomGroups(path, recursive)
         for value_progress in y:
             if not self.running:
--
libgit2 0.21.2