diff --git a/web/pgadmin/authenticate/internal.py b/web/pgadmin/authenticate/internal.py
index d63fd9204..105e78c4e 100644
--- a/web/pgadmin/authenticate/internal.py
+++ b/web/pgadmin/authenticate/internal.py
@@ -17,16 +17,18 @@ from flask_babelex import gettext
 
 from .registry import AuthSourceRegistry
 from pgadmin.model import User
+from pgadmin.utils.validation_utils import validate_email
 
 
 @six.add_metaclass(AuthSourceRegistry)
 class BaseAuthentication(object):
 
     DEFAULT_MSG = {
-        'USER_DOES_NOT_EXIST': 'Incorrect username or password.',
-        'LOGIN_FAILED': 'Login failed',
-        'EMAIL_NOT_PROVIDED': 'Email/Username not provided',
-        'PASSWORD_NOT_PROVIDED': 'Password not provided'
+        'USER_DOES_NOT_EXIST': gettext('Incorrect username or password.'),
+        'LOGIN_FAILED': gettext('Login failed'),
+        'EMAIL_NOT_PROVIDED': gettext('Email/Username not provided'),
+        'PASSWORD_NOT_PROVIDED': gettext('Password not provided'),
+        'INVALID_EMAIL': gettext('Email/Username is not valid')
     }
 
     @abstractproperty
@@ -85,7 +87,10 @@ class InternalAuthentication(BaseAuthentication):
 
     def validate(self, form):
         """User validation"""
-
+        # validate the email id first
+        if not validate_email(form.data['email']):
+            form.errors['email'] = [self.messages('INVALID_EMAIL')]
+            return False
         # Flask security validation
         return form.validate_on_submit()
 
diff --git a/web/pgadmin/misc/file_manager/__init__.py b/web/pgadmin/misc/file_manager/__init__.py
index c0fb4f721..9ededc1b2 100644
--- a/web/pgadmin/misc/file_manager/__init__.py
+++ b/web/pgadmin/misc/file_manager/__init__.py
@@ -18,6 +18,7 @@ from urllib.parse import unquote
 from sys import platform as _platform
 import config
 import codecs
+import pathlib
 from werkzeug.exceptions import InternalServerError
 
 import simplejson as json
@@ -317,6 +318,11 @@ class Filemanager(object):
     # Stores list of dict for filename & its encoding
     loaded_file_encoding_list = []
 
+    ERROR_NOT_ALLOWED = {
+        'Error': gettext('Not allowed'),
+        'Code': 0
+    }
+
     def __init__(self, trans_id):
         self.trans_id = trans_id
         self.patherror = encode_json(
@@ -822,10 +828,7 @@ class Filemanager(object):
         Rename file or folder
         """
         if not self.validate_request('rename'):
-            return {
-                'Error': gettext('Not allowed'),
-                'Code': 0
-            }
+            return self.ERROR_NOT_ALLOWED
 
         the_dir = self.dir if self.dir is not None else ''
 
@@ -883,10 +886,7 @@ class Filemanager(object):
         Delete file or folder
         """
         if not self.validate_request('delete'):
-            return {
-                'Error': gettext('Not allowed'),
-                'Code': 0
-            }
+            return self.ERROR_NOT_ALLOWED
 
         the_dir = self.dir if self.dir is not None else ''
         orig_path = "{0}{1}".format(the_dir, path)
@@ -924,10 +924,7 @@ class Filemanager(object):
         File upload functionality
         """
         if not self.validate_request('upload'):
-            return {
-                'Error': gettext('Not allowed'),
-                'Code': 0
-            }
+            return self.ERROR_NOT_ALLOWED
 
         the_dir = self.dir if self.dir is not None else ''
         err_msg = ''
@@ -940,6 +937,12 @@ class Filemanager(object):
             orig_path = "{0}{1}".format(the_dir, path)
             new_name = "{0}{1}".format(orig_path, file_name)
 
+            try:
+                # Check if the new file is inside the users directory
+                pathlib.Path(new_name).relative_to(the_dir)
+            except ValueError as _:
+                return self.ERROR_NOT_ALLOWED
+
             with open(new_name, 'wb') as f:
                 while True:
                     # 4MB chunk (4 * 1024 * 1024 Bytes)
@@ -1103,10 +1106,7 @@ class Filemanager(object):
         Functionality to create new folder
         """
         if not self.validate_request('create'):
-            return {
-                'Error': gettext('Not allowed'),
-                'Code': 0
-            }
+            return self.ERROR_NOT_ALLOWED
 
         the_dir = self.dir if self.dir is not None else ''
 
@@ -1156,10 +1156,7 @@ class Filemanager(object):
         Functionality to download file
         """
         if not self.validate_request('download'):
-            return {
-                'Error': gettext('Not allowed'),
-                'Code': 0
-            }
+            return self.ERROR_NOT_ALLOWED
 
         the_dir = self.dir if self.dir is not None else ''
         orig_path = "{0}{1}".format(the_dir, path)
diff --git a/web/pgadmin/setup/user_info.py b/web/pgadmin/setup/user_info.py
index ab38e567a..6aed075db 100644
--- a/web/pgadmin/setup/user_info.py
+++ b/web/pgadmin/setup/user_info.py
@@ -14,6 +14,8 @@ import os
 import re
 import getpass
 
+from pgadmin.utils.validation_utils import validate_email
+
 
 def user_info_desktop():
     print("NOTE: Configuring authentication for DESKTOP mode.")
@@ -43,14 +45,8 @@ def user_info_server():
             "pgAdmin user account:\n"
         )
 
-        email_filter = re.compile(
-            "^[a-zA-Z0-9.!#$%&'*+\\/=?^_`{|}~-]+@[a-zA-Z0-9]"
-            "(?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\\.[a-zA-Z0-9]"
-            "(?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*$"
-        )
-
         email = input("Email address: ")
-        while email == '' or not email_filter.match(email):
+        while not validate_email(email):
             print('Invalid email address. Please try again.')
             email = input("Email address: ")
 
diff --git a/web/pgadmin/tools/user_management/__init__.py b/web/pgadmin/tools/user_management/__init__.py
index 496a6afe5..df9e9c728 100644
--- a/web/pgadmin/tools/user_management/__init__.py
+++ b/web/pgadmin/tools/user_management/__init__.py
@@ -22,9 +22,10 @@ from werkzeug.exceptions import InternalServerError
 import config
 from pgadmin.utils import PgAdminModule
 from pgadmin.utils.ajax import make_response as ajax_response, \
-    make_json_response, bad_request, internal_server_error
+    make_json_response, bad_request, internal_server_error, forbidden
 from pgadmin.utils.csrf import pgCSRFProtect
 from pgadmin.utils.constants import MIMETYPE_APP_JS
+from pgadmin.utils.validation_utils import validate_email
 from pgadmin.model import db, Role, User, UserPreference, Server, \
     ServerGroup, Process, Setting
 
@@ -104,16 +105,11 @@ def validate_password(data, new_data):
 
 def validate_user(data):
     new_data = dict()
-    email_filter = re.compile(
-        "^[a-zA-Z0-9.!#$%&'*+\/=?^_`{|}~-]+@[a-zA-Z0-9]"
-        "(?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\.[a-zA-Z0-9]"
-        "(?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*$"
-    )
 
     validate_password(data, new_data)
 
     if 'email' in data and data['email'] and data['email'] != "":
-        if email_filter.match(data['email']):
+        if validate_email(data['email']):
             new_data['email'] = data['email']
         else:
             raise InternalServerError(_("Invalid email address."))
@@ -383,6 +379,18 @@ def update(uid):
         request.data, encoding='utf-8'
     )
 
+    # Username and email can not be changed for internal users
+    if usr.auth_source == current_app.PGADMIN_DEFAULT_AUTH_SOURCE:
+        non_editable_params = ('username', 'email')
+
+        for f in non_editable_params:
+            if f in data:
+                return forbidden(
+                    errmsg=_(
+                        "'{0}' is not allowed to modify."
+                    ).format(f)
+                )
+
     try:
         new_data = validate_user(data)
 
diff --git a/web/pgadmin/utils/paths.py b/web/pgadmin/utils/paths.py
index efc39a8bd..30bbcfa47 100644
--- a/web/pgadmin/utils/paths.py
+++ b/web/pgadmin/utils/paths.py
@@ -34,9 +34,18 @@ def get_storage_directory():
     if storage_dir is None:
         return None
 
-    username = current_user.username.split('@')[0]
-    if len(username) == 0 or username[0].isdigit():
-        username = 'pga_user_' + username
+    def _preprocess_username(un):
+        ret_un = un
+        if len(ret_un) == 0 or ret_un[0].isdigit():
+            ret_un = 'pga_user_' + username
+
+        ret_un = ret_un.replace('@', '_')\
+            .replace('/', 'slash')\
+            .replace('\\', 'slash')
+
+        return ret_un
+
+    username = _preprocess_username(current_user.username.split('@')[0])
 
     # Figure out the old-style storage directory name
     old_storage_dir = os.path.join(
@@ -45,11 +54,13 @@ def get_storage_directory():
         username
     )
 
+    username = _preprocess_username(current_user.username)
+
     # Figure out the new style storage directory name
     storage_dir = os.path.join(
         storage_dir.decode('utf-8') if hasattr(storage_dir, 'decode')
         else storage_dir,
-        current_user.username.replace('@', '_')
+        username
     )
 
     # Rename an old-style storage directory, if the new style doesn't exist
diff --git a/web/pgadmin/utils/validation_utils.py b/web/pgadmin/utils/validation_utils.py
new file mode 100644
index 000000000..4bb3f8574
--- /dev/null
+++ b/web/pgadmin/utils/validation_utils.py
@@ -0,0 +1,26 @@
+##########################################################################
+#
+# pgAdmin 4 - PostgreSQL Tools
+#
+# Copyright (C) 2013 - 2020, The pgAdmin Development Team
+# This software is released under the PostgreSQL Licence
+#
+##########################################################################
+
+import re
+
+
+def validate_email(email):
+    if email == '' or email is None:
+        return False
+
+    email_filter = re.compile(
+        "^[a-zA-Z0-9.!#$%&'*+\\/=?^_`{|}~-]+@[a-zA-Z0-9]"
+        "(?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\\.[a-zA-Z0-9]"
+        "(?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*$"
+    )
+
+    if not email_filter.match(email):
+        return False
+
+    return True