diff --git a/mayan/apps/converter/transformations.py b/mayan/apps/converter/transformations.py
index 48a44069ab..f791ed2c04 100644
--- a/mayan/apps/converter/transformations.py
+++ b/mayan/apps/converter/transformations.py
@@ -6,7 +6,7 @@ import logging
 from PIL import Image, ImageColor, ImageFilter
 
 from django.utils.translation import string_concat, ugettext_lazy as _
-from django.utils.encoding import force_text
+from django.utils.encoding import force_bytes, force_text
 
 logger = logging.getLogger(__name__)
 
@@ -62,14 +62,14 @@ class BaseTransformation(object):
             self.kwargs[argument_name] = kwargs.get(argument_name)
 
     def cache_hash(self):
-        result = hashlib.sha256(self.name)
+        result = hashlib.sha256(force_bytes(self.name))
 
         # Sort arguments for guaranteed repeatability
         for key, value in sorted(self.kwargs.items()):
-            result.update(force_text(key))
-            result.update(force_text(value))
+            result.update(force_bytes(key))
+            result.update(force_bytes(value))
 
-        return result.hexdigest()
+        return force_bytes(result.hexdigest())
 
     def execute_on(self, image):
         self.image = image
diff --git a/mayan/apps/lock_manager/backends/file_lock.py b/mayan/apps/lock_manager/backends/file_lock.py
index cc06c55f69..776d948c46 100644
--- a/mayan/apps/lock_manager/backends/file_lock.py
+++ b/mayan/apps/lock_manager/backends/file_lock.py
@@ -10,7 +10,7 @@ import uuid
 
 from django.conf import settings
 from django.core.files import locks
-from django.utils.encoding import force_text
+from django.utils.encoding import force_bytes, force_text
 
 from common.settings import setting_temporary_directory
 
@@ -23,7 +23,7 @@ lock = threading.Lock()
 logger = logging.getLogger(__name__)
 
 lock_file = os.path.join(
-    setting_temporary_directory.value, hashlib.sha256(settings.SECRET_KEY).hexdigest()
+    setting_temporary_directory.value, hashlib.sha256(force_bytes(settings.SECRET_KEY)).hexdigest()
 )
 open(lock_file, 'a').close()
 logger.debug('lock_file: %s', lock_file)