diff --git a/tests/system/shared/utils.py b/tests/system/shared/utils.py
index 2a17e0333c2..8639c6e2651 100644
--- a/tests/system/shared/utils.py
+++ b/tests/system/shared/utils.py
@@ -611,8 +611,12 @@ def stringify(obj):
     if isinstance(obj, stringTypes):
         return obj
     if isinstance(obj, bytes):
-        tmp = obj.decode('cp1252') if platform.system() in ('Microsoft','Windows') else obj.decode()
-        return tmp
+        if not platform.system() in ('Microsoft', 'Windows'):
+            return obj.decode()
+        try:
+            return obj.decode('cp1252')
+        except UnicodeDecodeError:
+            return obj.decode('utf-8')
 
 
 class GitClone:
diff --git a/tests/system/suite_editors/tst_edit_externally/test.py b/tests/system/suite_editors/tst_edit_externally/test.py
index dea2f5d8ec6..e04ab19670a 100644
--- a/tests/system/suite_editors/tst_edit_externally/test.py
+++ b/tests/system/suite_editors/tst_edit_externally/test.py
@@ -39,7 +39,10 @@ def main():
             test.fatal("Could not get the editor for '%s'" % currentFile,
                        "Skipping this file for now.")
             continue
+
         contentBefore = readFile(currentFile)
+        if not currentFile.endswith(".bin"):
+            contentBefore = stringify(contentBefore)
         if i % 2 == 0:
             # modify current file and store content for next modification
             formerContent = contentBefore