diff --git a/mayan/apps/storage/apps.py b/mayan/apps/storage/apps.py
index 2cc2965e07..c849a06760 100644
--- a/mayan/apps/storage/apps.py
+++ b/mayan/apps/storage/apps.py
@@ -5,5 +5,6 @@ from django.utils.translation import ugettext_lazy as _
 
 
 class StorageApp(apps.AppConfig):
+    has_tests = True
     name = 'mayan.apps.storage'
     verbose_name = _('Storage')
diff --git a/mayan/apps/storage/tests/__init__.py b/mayan/apps/storage/tests/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/mayan/apps/storage/tests/test_utils.py b/mayan/apps/storage/tests/test_utils.py
new file mode 100644
index 0000000000..b048edd053
--- /dev/null
+++ b/mayan/apps/storage/tests/test_utils.py
@@ -0,0 +1,80 @@
+from __future__ import print_function, unicode_literals
+
+from pathlib2 import Path
+import shutil
+
+from mayan.apps.common.tests.base import BaseTestCase
+from mayan.apps.storage.utils import mkdtemp
+
+from ..utils import patch_files
+
+
+class PatchFilesTestCase(BaseTestCase):
+    test_replace_text = 'replaced_text'
+
+    def setUp(self):
+        super(PatchFilesTestCase, self).setUp()
+
+        self.temporary_directory = mkdtemp()
+        self.path_temporary_directory = Path(self.temporary_directory)
+        self.path_test_file = self.path_temporary_directory / 'test_file.txt'
+
+        with self.path_test_file.open(mode='w') as file_object:
+            file_object.writelines(
+                [
+                    'line 1\n',
+                    '    line 2\n',
+                    'line 3\n',
+                ]
+            )
+
+    def tearDown(self):
+        super(PatchFilesTestCase, self).tearDown()
+        shutil.rmtree(self.temporary_directory, ignore_errors=True)
+
+    def _patch_test_file(self):
+        replace_list = [
+            {
+                'filename_pattern': '*',
+                'content_patterns': [
+                    {
+                        'search': self.test_search_text,
+                        'replace': self.test_replace_text,
+                    }
+                ]
+            }
+        ]
+        patch_files(
+            path=self.path_temporary_directory, replace_list=replace_list
+        )
+
+        with self.path_test_file.open(mode='r') as file_object:
+            self.final_text = file_object.read()
+
+    def test_file_patching_single_line(self):
+        self.test_search_text = 'line 1'
+
+        self._patch_test_file()
+
+        self.assertEqual(self.final_text, 'replaced_text\n    line 2\nline 3\n')
+
+    def test_file_patching_multi_line(self):
+        self.test_search_text = 'line 2\nline 3\n'
+
+        self._patch_test_file()
+
+        self.assertEqual(self.final_text, 'line 1\n    replaced_text')
+
+    def test_file_patching_spaces(self):
+        self.test_search_text = '    line 2'
+
+        self._patch_test_file()
+
+        self.assertEqual(self.final_text, 'line 1\nreplaced_text\nline 3\n')
+
+    def test_file_patching_no_matches(self):
+        self.test_search_text = 'line 4'
+
+        self._patch_test_file()
+
+        self.assertEqual(self.final_text, 'line 1\n    line 2\nline 3\n')
diff --git a/mayan/apps/storage/utils.py b/mayan/apps/storage/utils.py
index e288734c01..27175ba45c 100644
--- a/mayan/apps/storage/utils.py
+++ b/mayan/apps/storage/utils.py
@@ -1,6 +1,5 @@
 from __future__ import unicode_literals
 
-import fileinput
 import logging
 import os
 import shutil
@@ -8,7 +7,6 @@ import tempfile
 
 from pathlib2 import Path
 
-from django.utils.encoding import force_text
 from django.utils.module_loading import import_string
 
 from .settings import setting_temporary_directory
@@ -74,15 +72,42 @@ def patch_files(path=None, replace_list=None):
     for replace_entry in replace_list or []:
         for path_entry in path_object.glob('**/{}'.format(replace_entry['filename_pattern'])):
             if path_entry.is_file():
-                # PY3
-                # Don't use context processor to allow working on Python 2.7
-                # Update on Mayan EDMS version >= 4.0
-                file_object = fileinput.FileInput(force_text(path_entry), inplace=True)
-                for line in file_object:
-                    for pattern in replace_entry['content_patterns']:
-                        line = line.replace(pattern['search'], pattern['replace'])
-                    print(line, end='')
-                file_object.close()
+                for pattern in replace_entry['content_patterns']:
+                    with path_entry.open(mode='r+') as source_file_object:
+                        with tempfile.TemporaryFile(mode='r+') as temporary_file_object:
+                            source_position = 0
+                            destination_position = 0
+
+                            while(True):
+                                source_file_object.seek(source_position)
+                                letter = source_file_object.read(1)
+
+                                if len(letter) == 0:
+                                    break
+                                else:
+                                    if letter == pattern['search'][0]:
+                                        text = '{}{}'.format(letter, source_file_object.read(len(pattern['search']) - 1))
+
+                                        temporary_file_object.seek(destination_position)
+                                        if text == pattern['search']:
+                                            text = pattern['replace']
+                                            source_position = source_position + len(pattern['search'])
+                                            destination_position = destination_position + len(pattern['replace'])
+                                            temporary_file_object.write(text)
+
+                                        else:
+                                            source_position = source_position + 1
+                                            destination_position = destination_position + 1
+                                            temporary_file_object.write(letter)
+                                    else:
+                                        source_position = source_position + 1
+                                        destination_position = destination_position + 1
+                                        temporary_file_object.write(letter)
+
+                            source_file_object.seek(0)
+                            source_file_object.truncate()
+                            temporary_file_object.seek(0)
+                            shutil.copyfileobj(fsrc=temporary_file_object, fdst=source_file_object)
 
 
 def validate_path(path):