diff --git a/bottles/frontend/main.py b/bottles/frontend/main.py
index 9486c4206e..9874d8b84e 100644
--- a/bottles/frontend/main.py
+++ b/bottles/frontend/main.py
@@ -29,7 +29,7 @@
 gi.require_version("Xdp", "1.0")
 # gi.require_version("XdpGtk4", "1.0")
 
-from gi.repository import Gtk, Gio, GLib, GObject, Adw, Xdp  # type: ignore
+from gi.repository import Gtk, Gio, GLib, GObject, Adw  # type: ignore
 
 from bottles.frontend.params import *
 from bottles.backend.logger import Logger
@@ -251,12 +251,6 @@ def do_activate(self):
             win = MainWindow(application=self, arg_bottle=self.arg_bottle)
         self.win = win
 
-        # Be VERY explicit that non-sandboxed environments are unsupported
-        if not Xdp.Portal.running_under_sandbox():
-            logging.error(_("Bottles is only supported within a sandboxed format. Official sources of Bottles are available at:"))
-            logging.error("https://usebottles.com/download/")
-            quit(1)
-
         win.present()
 
     def __quit(self, *args):
diff --git a/bottles/frontend/windows/main_window.py b/bottles/frontend/windows/main_window.py
index 5fb9a15c29..047fc6a819 100644
--- a/bottles/frontend/windows/main_window.py
+++ b/bottles/frontend/windows/main_window.py
@@ -21,7 +21,7 @@
 from gettext import gettext as _
 from typing import Optional
 
-from gi.repository import Gtk, GLib, Gio, Adw, GObject, Gdk
+from gi.repository import Gtk, GLib, Gio, Adw, GObject, Gdk, Xdp
 
 from bottles.backend.globals import Paths
 from bottles.backend.health import HealthChecker
@@ -96,6 +96,28 @@ def __init__(self, arg_bottle, **kwargs):
             manager = Adw.StyleManager.get_default()
             manager.set_color_scheme(Adw.ColorScheme.FORCE_DARK)
 
+        # Be VERY explicit that non-sandboxed environments are unsupported
+        if not Xdp.Portal.running_under_sandbox():
+            def response(dialog, response, *args):
+                if response == "close":
+                    quit(1)
+
+            body = _("Bottles is only supported within a sandboxed environment. Official sources of Bottles are available at")
+            download_url = "usebottles.com/download"
+
+            error_dialog = Adw.AlertDialog.new(
+                _("Unsupported Environment"),
+                f"{body} <a href='https://{download_url}' title='https://{download_url}'>{download_url}.</a>"
+            )
+
+            error_dialog.add_response("close", _("Close"))
+            error_dialog.set_body_use_markup(True)
+            error_dialog.connect("response", response)
+            error_dialog.present(self)
+            logging.error(_("Bottles is only supported within a sandboxed format. Official sources of Bottles are available at:"))
+            logging.error("https://usebottles.com/download/")
+            return
+
         # Loading view
         self.page_loading = LoadingView()