diff --git a/osa_toolkit/filesystem.py b/osa_toolkit/filesystem.py
index 4e30046bb8..b7742db70b 100644
--- a/osa_toolkit/filesystem.py
+++ b/osa_toolkit/filesystem.py
@@ -193,7 +193,7 @@ def write_hostnames(save_path, hostnames_ips):
                 indent=4,
                 separators=(',', ': '),
                 sort_keys=True
-            )
+            ).encode('ascii')
         )
 
 
@@ -212,7 +212,7 @@ def _load_from_json(filename, preferred_path=None, raise_if_missing=True):
     dictionary = False
     if target_file is not False:
         with open(target_file, 'rb') as f_handle:
-            dictionary = json.loads(f_handle.read())
+            dictionary = json.loads(f_handle.read().decode('ascii'))
 
     return dictionary, target_file
 
@@ -264,7 +264,7 @@ def save_inventory(inventory_json, save_path):
     else:
         inventory_file = os.path.join(save_path, INVENTORY_FILENAME)
     with open(inventory_file, 'wb') as f:
-        f.write(inventory_json)
+        f.write(inventory_json.encode('ascii'))
         logger.info("Inventory written")
 
 
diff --git a/tests/test_inventory.py b/tests/test_inventory.py
index 5d0a3e1244..4f2b864212 100644
--- a/tests/test_inventory.py
+++ b/tests/test_inventory.py
@@ -570,7 +570,7 @@ class TestConfigCheckBase(unittest.TestCase):
         self.config_changed = True
         # Save new user_config_file
         with open(USER_CONFIG_FILE, 'wb') as f:
-            f.write(yaml.dump(self.user_defined_config))
+            f.write(yaml.dump(self.user_defined_config).encode('ascii'))
 
     def restore_config(self):
         # get back our initial user config file