diff --git a/nvflare/app_common/state_persistors/__init__.py b/nvflare/app_common/state_persistors/__init__.py
index e69de29bb2d..2b8f6c7e874 100644
--- a/nvflare/app_common/state_persistors/__init__.py
+++ b/nvflare/app_common/state_persistors/__init__.py
@@ -0,0 +1,13 @@
+# Copyright (c) 2021-2022, NVIDIA CORPORATION.  All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
diff --git a/nvflare/app_common/state_persistors/storage_state_persistor.py b/nvflare/app_common/state_persistors/storage_state_persistor.py
index bb8a6e833ae..abadabccb8f 100644
--- a/nvflare/app_common/state_persistors/storage_state_persistor.py
+++ b/nvflare/app_common/state_persistors/storage_state_persistor.py
@@ -24,7 +24,6 @@
 class StorageStatePersistor(StatePersistor):
     def __init__(self, storage: StorageSpec, location: str):
         self.storage = storage
-
         self.location = location
 
         if not os.path.isabs(location):
@@ -36,7 +35,6 @@ def save(self, snapshot: FLSnapshot) -> str:
             snapshot: FLSnapshot object
         Returns: storage location
         """
-        # snapshot_uri_timestamp = "snapshot-" + datetime.datetime.now().strftime("%Y-%m-%d,%H:%M:%S")
         self.storage.create_object(
             uri=self.location, data=pickle.dumps(snapshot), meta={}, overwrite_existing=True
         )
diff --git a/nvflare/app_common/storages/filesystem_storage.py b/nvflare/app_common/storages/filesystem_storage.py
index c1f97d1f55c..808b51f0e79 100644
--- a/nvflare/app_common/storages/filesystem_storage.py
+++ b/nvflare/app_common/storages/filesystem_storage.py
@@ -56,20 +56,20 @@ def _write(self, path: str, content):
         try:
             Path(os.path.dirname(path)).mkdir(parents=True, exist_ok=True)
             with open(path + "_tmp", "wb") as f:
-                f.write(pickle.dumps(content))
+                f.write(content)
                 f.flush()
                 os.fsync(f.fileno())
-            if os.path.isfile(path):
-                os.remove(path)
         except Exception as e:
+            if os.path.isfile(path + "_tmp"):
+                os.remove(path + "_tmp")
             raise IOError("failed to write content: {}".format(e))
 
         os.rename(path + "_tmp", path)
 
-    def _read(self, path: str) -> object:
+    def _read(self, path: str) -> bytes:
         try:
             with open(path, "rb") as f:
-                content = pickle.load(f)
+                content = f.read()
         except Exception as e:
             raise IOError("failed to read content: {}".format(e))
 
@@ -114,7 +114,11 @@ def create_object(self, uri: str, data: ByteString, meta: dict, overwrite_existi
         meta_path = os.path.join(full_uri, "meta")
 
         self._write(data_path + "_tmp", data)
-        self._write(meta_path, meta)
+        try:
+            self._write(meta_path, pickle.dumps(meta))
+        except Exception as e:
+            os.remove(data_path + "_tmp")
+            raise e
         os.rename(data_path + "_tmp", data_path)
 
     def update_meta(self, uri: str, meta: dict, replace: bool):
@@ -140,11 +144,11 @@ def update_meta(self, uri: str, meta: dict, replace: bool):
             raise Exception("object {} does not exist".format(uri))
 
         if replace:
-            self._write(os.path.join(full_uri, "meta"), meta)
+            self._write(os.path.join(full_uri, "meta"), pickle.dumps(meta))
         else:
             prev_meta = self.get_meta(uri)
             prev_meta.update(meta)
-            self._write(os.path.join(full_uri, "meta"), prev_meta)
+            self._write(os.path.join(full_uri, "meta"), pickle.dumps(prev_meta))
 
     def update_data(self, uri: str, data: ByteString):
         """Update the data info of the specified object
@@ -201,7 +205,7 @@ def get_meta(self, uri: str) -> dict:
         if not self._object_exists(full_uri):
             raise Exception("object {} does not exist".format(uri))
 
-        return self._read(os.path.join(full_uri, "meta"))
+        return pickle.loads(self._read(os.path.join(full_uri, "meta")))
 
     def get_full_meta(self, uri: str) -> dict:
         """Get full meta info of the specified object