diff --git a/data/meson.build b/data/meson.build
index ea7db46..22e446a 100644
--- a/data/meson.build
+++ b/data/meson.build
@@ -41,14 +41,18 @@ desktop_file = i18n.merge_file(
   install_dir: join_paths(get_option('datadir'), 'applications'),
 )
 
-custom_target(
-  'install-autostart-desktop',
-  input: desktop_file,
+# System-wide autostart entry (XDG autostart, not copied per-user via skel).
+# The app self-gates on launch: with --autostart it exits immediately when the
+# per-user completion marker exists or when running in a live session. A
+# per-user file of the same name in ~/.config/autostart (from pre-0.2.16 skel
+# copies) shadows this entry per the XDG autostart spec.
+autostart_file = i18n.merge_file(
+  input: 'org.frostyard.FirstSetup.autostart.desktop.in',
   output: 'org.frostyard.FirstSetup.autostart.desktop',
-  command: ['cp', '@INPUT@', '@OUTPUT@'],
-  install_dir: join_paths(get_option('sysconfdir'), 'skel', '.config', 'autostart'),
-  build_by_default: true,
-  install : true,
+  type: 'desktop',
+  po_dir: '../po',
+  install: true,
+  install_dir: join_paths(get_option('sysconfdir'), 'xdg', 'autostart'),
 )
 
 desktop_utils = find_program('desktop-file-validate', required: false)
@@ -56,6 +60,9 @@ if desktop_utils.found()
   test('Validate desktop file', desktop_utils,
     args: [desktop_file]
   )
+  test('Validate autostart desktop file', desktop_utils,
+    args: [autostart_file]
+  )
 endif
 
 install_data(
diff --git a/data/org.frostyard.FirstSetup.autostart.desktop.in b/data/org.frostyard.FirstSetup.autostart.desktop.in
new file mode 100644
index 0000000..0e04ec7
--- /dev/null
+++ b/data/org.frostyard.FirstSetup.autostart.desktop.in
@@ -0,0 +1,9 @@
+[Desktop Entry]
+Name=SNOW First Setup
+Exec=snow-first-setup --autostart
+Icon=org.frostyard.FirstSetup
+Terminal=false
+Type=Application
+Categories=System;GTK;
+StartupNotify=true
+NoDisplay=true
diff --git a/debian/snow-first-setup.maintscript b/debian/snow-first-setup.maintscript
new file mode 100644
index 0000000..918d724
--- /dev/null
+++ b/debian/snow-first-setup.maintscript
@@ -0,0 +1 @@
+rm_conffile /etc/skel/.config/autostart/org.frostyard.FirstSetup.autostart.desktop 0.2.16~
diff --git a/snow_first_setup/application.py b/snow_first_setup/application.py
index 9b7af6c..bbb406d 100644
--- a/snow_first_setup/application.py
+++ b/snow_first_setup/application.py
@@ -100,6 +100,14 @@ def __register_arguments(self):
             _("Force the regular mode, independant of group."),
             None,
         )
+        self.add_main_option(
+            "autostart",
+            ord("a"),
+            GLib.OptionFlags.NONE,
+            GLib.OptionArg.NONE,
+            _("Launched by the system autostart entry; exits early if setup is already complete (handled in main)."),
+            None,
+        )
         self.add_main_option(
             "oem-mode",
             ord("o"),
diff --git a/snow_first_setup/core/backend.py b/snow_first_setup/core/backend.py
index 64b00b1..1a6dbef 100644
--- a/snow_first_setup/core/backend.py
+++ b/snow_first_setup/core/backend.py
@@ -46,6 +46,19 @@ def set_hostname(hostname: str):
 def set_theme(theme: str) -> str|None:
     return run_script("theme", [theme])
 
+def setup_complete_marker_path() -> str:
+    """Path of the per-user marker written when first setup completes.
+
+    The system-wide autostart entry (installed to /etc/xdg/autostart) launches
+    the app with --autostart, which exits immediately when this marker exists.
+    """
+    config_home = os.environ.get("XDG_CONFIG_HOME") or os.path.expanduser("~/.config")
+    return os.path.join(config_home, "snow-first-setup.done")
+
+def is_setup_complete() -> bool:
+    """Check whether the current user already completed first setup."""
+    return os.path.exists(setup_complete_marker_path())
+
 def is_live_session() -> bool:
     """Check if the system is running in live session mode.
 
@@ -83,8 +96,8 @@ def remove_first_setup_user():
 def oem_complete():
     return run_script("oemcomplete", [], root=True)
 
-def remove_autostart_file():
-    return run_script("remove-autostart-file", [])
+def mark_setup_complete():
+    return run_script("complete-setup", [])
 
 def _setup_system():
     return run_script("setup-system", [])
diff --git a/snow_first_setup/main.py b/snow_first_setup/main.py
index 77459fa..ce124ff 100644
--- a/snow_first_setup/main.py
+++ b/snow_first_setup/main.py
@@ -29,6 +29,15 @@ def main(version, moduledir: str, localedir: str):
         sys.exit(1)
         return
 
+    # When launched via the system-wide autostart entry (/etc/xdg/autostart),
+    # exit immediately if this user already completed first setup or if this
+    # is a live session (the live media runs the installer instead). Checked
+    # before any GTK/resource loading so the gate is essentially free.
+    if "--autostart" in sys.argv:
+        import snow_first_setup.core.backend as early_backend
+        if early_backend.is_setup_complete() or early_backend.is_live_session():
+            return 0
+
     signal.signal(signal.SIGINT, signal.SIG_DFL)
     locale.bindtextdomain('snow-first-setup', localedir)
     locale.textdomain('snow-first-setup')
diff --git a/snow_first_setup/scripts/complete-setup b/snow_first_setup/scripts/complete-setup
new file mode 100755
index 0000000..f7ee20a
--- /dev/null
+++ b/snow_first_setup/scripts/complete-setup
@@ -0,0 +1,24 @@
+#!/bin/bash
+if ! [ -z "$1" ]; then
+    echo "usage:"
+    echo "complete-setup"
+    exit 5
+fi
+
+if [ "$UID" == "0" ]; then
+    echo "this script must be run as a regular user"
+    exit 7
+fi
+
+config_home="${XDG_CONFIG_HOME:-$HOME/.config}"
+
+# Record per-user completion. The system-wide autostart entry in
+# /etc/xdg/autostart launches the app with --autostart, which exits
+# immediately when this marker exists.
+mkdir -p "$config_home"
+touch "$config_home/snow-first-setup.done"
+
+# Legacy cleanup: users provisioned before v0.2.16 received a per-user
+# autostart copy via /etc/skel; remove it if present so it no longer
+# shadows (or duplicates) the system-wide entry.
+rm -f "$config_home/autostart/org.frostyard.FirstSetup.autostart.desktop"
diff --git a/snow_first_setup/scripts/meson.build b/snow_first_setup/scripts/meson.build
index b489d32..e392180 100755
--- a/snow_first_setup/scripts/meson.build
+++ b/snow_first_setup/scripts/meson.build
@@ -18,7 +18,7 @@ sources = [
   'setup-system',
   'user',
   'remove-first-setup-user',
-  'remove-autostart-file',
+  'complete-setup',
   'install-to-disk',
   'enroll-key',
   'recovery-key',
diff --git a/snow_first_setup/scripts/remove-autostart-file b/snow_first_setup/scripts/remove-autostart-file
deleted file mode 100755
index c282901..0000000
--- a/snow_first_setup/scripts/remove-autostart-file
+++ /dev/null
@@ -1,13 +0,0 @@
-#!/bin/bash
-if ! [ -z "$1" ]; then
-    echo "usage:"
-    echo "remove-autostart-file"
-    exit 5
-fi
-
-if [ "$UID" == "0" ]; then
-    echo "this script must be run as a regular user"
-    exit 7
-fi
-
-rm ~/.config/autostart/org.frostyard.FirstSetup.autostart.desktop
diff --git a/snow_first_setup/views/progress.py b/snow_first_setup/views/progress.py
index b62966a..5a0a13a 100644
--- a/snow_first_setup/views/progress.py
+++ b/snow_first_setup/views/progress.py
@@ -33,7 +33,7 @@ class VanillaProgress(Adw.Bin):
     __not_started = True
     __finished = False
     __already_skipped = False
-    __already_removed_autostart_file = False
+    __already_marked_complete = False
 
     def __init__(self, window, **kwargs):
         super().__init__(**kwargs)
@@ -52,8 +52,8 @@ def set_page_inactive(self):
         return
 
     def finish(self):
-        if not self.__already_removed_autostart_file:
-            self.__already_removed_autostart_file = backend.remove_autostart_file()
+        if not self.__already_marked_complete:
+            self.__already_marked_complete = backend.mark_setup_complete()
         return True
 
     def __on_items_changed_thread(self, id: str, uid: str, state: backend.ProgressState, info: dict):