diff --git a/desktop_shop/gui/callbacks.py b/desktop_shop/gui/callbacks.py
index a9e8c90..faea54f 100644
--- a/desktop_shop/gui/callbacks.py
+++ b/desktop_shop/gui/callbacks.py
@@ -50,7 +50,7 @@ def sign_out():
     """
     gui.app.data = {
         "session_id": None,
-        "user_data": user.UserSignUpData(),
+        "user_data": None,
         "pw_hash": "",
         "cart": [],
     }
diff --git a/desktop_shop/gui/init.py b/desktop_shop/gui/init.py
index 8aa7dd0..7684a00 100644
--- a/desktop_shop/gui/init.py
+++ b/desktop_shop/gui/init.py
@@ -7,7 +7,7 @@
 import tkinter as tk
 from typing import Dict
 
-from desktop_shop import gui, user
+from desktop_shop import gui
 from desktop_shop.gui import components, config
 from desktop_shop.gui.components import Builder, Component, EntryFactory, Factory, Frame
 from desktop_shop.gui.views import views
@@ -62,7 +62,7 @@ def init():
     gui.app.views_dict = init_views(gui.root, gui.app.builder)
     gui.app.data = {
         "session_id": None,
-        "user_data": user.UserSignUpData(),
+        "user_data": None,
         "pw_hash": "",
         "cart": [],
     }
diff --git a/desktop_shop/user.py b/desktop_shop/user.py
index 9a6d458..b925710 100644
--- a/desktop_shop/user.py
+++ b/desktop_shop/user.py
@@ -11,13 +11,10 @@
 # pylint: disable=function-redefined
 @dataclass
 class UserData:
-    """Stores user data
+    """Stores user data"""
 
-    FIXME: crashes when first_name or last_name are accessed without being set.
-    """
-
-    first_name: str = ""
-    last_name: str = ""
+    first_name: str
+    last_name: str
     gender: str = ""
     dob: str = ""  # date of birth
     email: str = ""
diff --git a/tests/unit/gui/callbacks_test.py b/tests/unit/gui/callbacks_test.py
index 341f1ea..9e4105d 100644
--- a/tests/unit/gui/callbacks_test.py
+++ b/tests/unit/gui/callbacks_test.py
@@ -176,7 +176,7 @@ def test_store_user_data_error():
 @pytest.mark.parametrize(
     "user_data, expected_message_start, expected",
     [
-        (UserSignUpData(), "Email", False),
+        (UserSignUpData(first_name="a", last_name="b"), "Email", False),
         (UserSignUpData(email="a@b.c", first_name="1eer3", last_name="2aa4"), "First", False),
         (UserSignUpData(email="a@b.c", first_name="john", last_name="2bbere4 "), "Last", False),
         (UserSignUpData(email="a@b.c", first_name="john", last_name="doe"), "", True),