diff --git a/pyrit/ui/app.py b/pyrit/ui/app.py
index 9c0b743a07..20beceac7f 100644
--- a/pyrit/ui/app.py
+++ b/pyrit/ui/app.py
@@ -5,6 +5,8 @@
 import subprocess
 import sys
 import traceback
+import ctypes
+import ctypes
 
 GLOBAL_MUTEX_NAME = "PyRIT-Gradio"
 
@@ -25,15 +27,18 @@ def launch_app(open_browser: bool = False) -> None:
         subprocess.Popen([python_path, current_path, str(open_browser)])
 
 
-def is_app_running() -> bool:
+def create_mutex() -> bool:
     if sys.platform != "win32":
-        raise NotImplementedError("This function is only supported on Windows.")
+        return True
+    last_error = ctypes.windll.kernel32.GetLastError()
+    return bool(last_error != 183)  # ERROR_ALREADY_EXISTS
+
 
-    import ctypes.wintypes  # noqa: F401
+def is_app_running() -> bool:
+    if sys.platform != "win32":
+        return False
 
     SYNCHRONIZE = 0x00100000
-    mutex = ctypes.windll.kernel32.OpenMutexW(SYNCHRONIZE, False, GLOBAL_MUTEX_NAME)
-    if not mutex:
         return False
 
     # Close the handle to the mutex
@@ -43,17 +48,6 @@ def is_app_running() -> bool:
 
 if __name__ == "__main__":
 
-    def create_mutex() -> bool:
-        if sys.platform != "win32":
-            raise NotImplementedError("This function is only supported on Windows.")
-
-        # TODO make sure to add cross-platform support for this.
-        import ctypes.wintypes
-
-        ctypes.windll.kernel32.CreateMutexW(None, False, GLOBAL_MUTEX_NAME)
-        last_error = ctypes.windll.kernel32.GetLastError()
-        return bool(last_error != 183)  # ERROR_ALREADY_EXISTS
-
     if not create_mutex():
         print("Gradio UI is already running.")
         sys.exit(1)
diff --git a/tests/unit/ui/test_app.py b/tests/unit/ui/test_app.py
new file mode 100644
index 0000000000..94b28fc29e
--- /dev/null
+++ b/tests/unit/ui/test_app.py
@@ -0,0 +1,16 @@
+# Copyright (c) Microsoft Corporation.
+# Licensed under the MIT license.
+
+from pyrit.ui import app as ui_app
+
+
+def test_is_app_running_returns_false_on_non_windows(monkeypatch):
+    monkeypatch.setattr(ui_app.sys, "platform", "linux")
+
+    assert ui_app.is_app_running() is False
+
+
+def test_create_mutex_returns_true_on_non_windows(monkeypatch):
+    monkeypatch.setattr(ui_app.sys, "platform", "linux")
+
+    assert ui_app.create_mutex() is True