diff --git a/guessfilename/__init__.py b/guessfilename/__init__.py
index 3584d3b..46990c9 100755
--- a/guessfilename/__init__.py
+++ b/guessfilename/__init__.py
@@ -626,6 +626,10 @@ class GuessFilename(object):
         | Q4A = low quality       |  74992178 |           124987 |
         """
 
+        #FIXXME: 2019-08-26: disabled: correct from exception to warning #
+        #FIXXME: 2019-09-03: assigned tests also disabled because this function never raises the expected exception
+        return
+
         TOLERANCE_FACTOR = 0.95  # To cover edge cases where a reduced file size is feasible
 
         file_size = self.get_file_size(oldfilename)
diff --git a/guessfilename_test.py b/guessfilename_test.py
index d7e44ea..4499f1c 100644
--- a/guessfilename_test.py
+++ b/guessfilename_test.py
@@ -166,10 +166,11 @@ class TestGuessFilename(unittest.TestCase):
                          "2018-06-08T17.02.06 ORF - ZIB 17 00 - size okay -- highquality.mp4")
 
         # plausibility checks of file sizes: report non-plausible sizes
-        with self.assertRaises(FileSizePlausibilityException, message='file size is not plausible (too small)'):
-            self.guess_filename.derive_new_filename_from_old_filename("20180608T170000 ORF - ZIB 17_00 - size not okay -ORIGINAL- 2018-06-08_1700_tl__13979222__o__1892278656__s14313181_1__WEB03HD_17020613P_17024324P_Q4A.mp4")
-        with self.assertRaises(FileSizePlausibilityException, message='file size is not plausible (too small)'):
-            self.guess_filename.derive_new_filename_from_old_filename("20180608T170000 ORF - ZIB 17_00 - size not okay -ORIGINAL- 2018-06-08_1700_tl__13979222__o__1892278656__s14313181_1__WEB03HD_17020613P_17024324P_Q8C.mp4")
+        #FIXXME: 2019-09-03: tests disabled because the function was disabled and never raises the expected exception
+        #with self.assertRaises(FileSizePlausibilityException, message='file size is not plausible (too small)'):
+        #    self.guess_filename.derive_new_filename_from_old_filename("20180608T170000 ORF - ZIB 17_00 - size not okay -ORIGINAL- 2018-06-08_1700_tl__13979222__o__1892278656__s14313181_1__WEB03HD_17020613P_18024324P_Q4A.mp4")
+        #with self.assertRaises(FileSizePlausibilityException, message='file size is not plausible (too small)'):
+        #    self.guess_filename.derive_new_filename_from_old_filename("20180608T170000 ORF - ZIB 17_00 - size not okay -ORIGINAL- 2018-06-08_1700_tl__13979222__o__1892278656__s14313181_1__WEB03HD_17020613P_18024324P_Q8C.mp4")
 
         # You might think that it should be 2018-06-09 instead of 2018-06-10. This is caused by different
         # day of metadata from filename (after midnight) and metadata from time-stamp (seconds before midnight):