diff --git a/filetags/__init__.py b/filetags/__init__.py
index 4585d3e..6d2b6bc 100755
--- a/filetags/__init__.py
+++ b/filetags/__init__.py
@@ -2520,7 +2520,7 @@ def assert_empty_tagfilter_directory(directory):
             logging.debug('re-creating tagfilter directory "%s" ...' % str(directory))
             os.makedirs(directory)
 
-    with open(id, 'w'):
+    with open(id, 'w', encoding="utf-8"):
         pass
 
     if not options.dryrun:
diff --git a/tests/unit_tests.py b/tests/unit_tests.py
index 20f5308..9d9771d 100755
--- a/tests/unit_tests.py
+++ b/tests/unit_tests.py
@@ -354,7 +354,7 @@ class TestLocateAndParseControlledVocabulary(unittest.TestCase):
     def create_file(self, name, content):
 
         assert(os.path.isdir(os.path.dirname(name)))
-        with open(name, 'w') as outputhandle:
+        with open(name, 'w', encoding="utf-8") as outputhandle:
             outputhandle.write(content)
 
     def test_find_cv_in_startfile_dir_instead_of_cwd(self):
@@ -613,7 +613,7 @@ class TestFileWithoutTags(unittest.TestCase):
 
     def create_tmp_file(self, name):
 
-        with open(os.path.join(self.tempdir, name), 'w') as outputhandle:
+        with open(os.path.join(self.tempdir, name), 'w', encoding="utf-8") as outputhandle:
             outputhandle.write('This is a test file for filetags unit testing')
 
     def file_exists(self, name):
@@ -825,7 +825,7 @@ class TestHierarchyWithFilesAndFolders(unittest.TestCase):
 
     def create_tmp_file(self, directory, name):
 
-        with open(os.path.join(directory, name), 'w') as outputhandle:
+        with open(os.path.join(directory, name), 'w', encoding="utf-8") as outputhandle:
             outputhandle.write('This is a test file for filetags unit testing')
 
     def file_exists(self, name):
@@ -937,7 +937,7 @@ class TestHierarchyWithFilesAndFolders(unittest.TestCase):
 
     def test_tagtrees_overwrites_old_default_directory(self):
 
-        with open(os.path.join(self.subdir2, 'boring tagtrees data.txt'), 'w'):
+        with open(os.path.join(self.subdir2, 'boring tagtrees data.txt'), 'w', encoding="utf-8"):
             pass
 
         filetags.generate_tagtrees(directory=self.subdir2,
@@ -952,7 +952,7 @@ class TestHierarchyWithFilesAndFolders(unittest.TestCase):
 
         filetags.options.tagtrees_directory = self.subdir2
 
-        with open(os.path.join(self.subdir2, '.filetags_tagtrees'), 'w'):
+        with open(os.path.join(self.subdir2, '.filetags_tagtrees'), 'w', encoding="utf-8"):
             pass
 
         filetags.generate_tagtrees(directory=self.subdir2,
@@ -969,7 +969,7 @@ class TestHierarchyWithFilesAndFolders(unittest.TestCase):
 
         filetags.options.tagtrees_directory = self.subdir2
 
-        with open(os.path.join(self.subdir2, 'critical data.txt'), 'w'):
+        with open(os.path.join(self.subdir2, 'critical data.txt'), 'w', encoding="utf-8"):
             pass
 
         with self.assertRaises(SystemExit):
@@ -1055,7 +1055,7 @@ class TestReplacingLinkSourceAndTarget(unittest.TestCase):
 
     def create_source_file(self, name):
 
-        with open(os.path.join(self.sourcedir, name), 'w') as outputhandle:
+        with open(os.path.join(self.sourcedir, name), 'w', encoding="utf-8") as outputhandle:
             outputhandle.write('This is a test file for filetags unit testing')
 
     def create_link_file(self, source, destination):