diff --git a/app/Modules/Files/Access/StaffLibraryScope.php b/app/Modules/Files/Access/StaffLibraryScope.php
index de214d56..486075ff 100644
--- a/app/Modules/Files/Access/StaffLibraryScope.php
+++ b/app/Modules/Files/Access/StaffLibraryScope.php
@@ -268,6 +268,15 @@ class StaffLibraryScope
      * row rather than from the assignment ignores the dead ones by
      * construction, which is also the right answer: a deleted file is
      * not reach, because nobody can reach it.
+     *
+     * An expired file is the same answer for the same reason. Membership
+     * in this group grants nobody access to it — File::scopeVisibleToClient
+     * ends in notExpired(), so it is gone from every member's /my-files and
+     * the download is refused — while its absence from files() otherwise
+     * reads as "outside my library" and locks the group exactly as a
+     * deleted file used to. Expiry is reversible where deletion is not, so
+     * the file counts as reach again the moment it does: this asks what is
+     * reachable now, at the moment somebody is added or removed.
      */
     private function groupReachesNoFurther(User $user, Group $group): bool
     {
@@ -282,6 +291,7 @@ class StaffLibraryScope
 
         $outside = File::query()
             ->whereIn('id', $assignedFiles)
+            ->notExpired()
             ->whereNotIn('id', $this->files($user)->select('id'))
             ->exists();
 
diff --git a/tests/Feature/Groups/GroupMembershipScopeTest.php b/tests/Feature/Groups/GroupMembershipScopeTest.php
index 06507824..0aaf5fa5 100644
--- a/tests/Feature/Groups/GroupMembershipScopeTest.php
+++ b/tests/Feature/Groups/GroupMembershipScopeTest.php
@@ -325,6 +325,58 @@ test('a deleted file does not excuse a live one that is still out of reach', fun
         ->assertForbidden();
 });
 
+// Expiry is the same answer for the same reason: membership grants nobody
+// access to an expired file, because scopeVisibleToClient ends in
+// notExpired(). It is only invisible to files(), which read as reach.
+test('a group is not locked shut by a file that has since expired', function () {
+    $group = Group::query()->create(['name' => 'Seasonal', 'slug' => 'seasonal', 'public' => false]);
+    $group->members()->syncWithoutDetaching([$this->mine->id]);
+
+    $file = uploadNamedFile($this->admin, 'summer-offer');
+    shareFileWithGroup($file, $group);
+
+    $second = User::factory()->client()->create(['name' => 'Also Mine']);
+    $this->rep->assignedClients()->attach($second->id);
+
+    $this->actingAs($this->rep)
+        ->post("/groups/{$group->id}/members", ['user_id' => $second->id])
+        ->assertRedirect();
+
+    $file->update(['expires_at' => now()->subDay()]);
+
+    // Nobody in the group can reach it any more — the premise of the rule.
+    $this->actingAs($this->mine)->get("/files/{$file->id}/download")->assertForbidden();
+
+    $third = User::factory()->client()->create(['name' => 'Mine Too']);
+    $this->rep->assignedClients()->attach($third->id);
+
+    $this->actingAs($this->rep)
+        ->post("/groups/{$group->id}/members", ['user_id' => $third->id])
+        ->assertRedirect();
+
+    expect($group->members()->count())->toBe(3);
+
+    // And taking their own client out again, which is the part that reads
+    // worst: the rep could not undo their own membership change.
+    $this->actingAs($this->rep)
+        ->delete("/groups/{$group->id}/members/{$third->id}")
+        ->assertRedirect();
+
+    expect($group->members()->count())->toBe(2);
+});
+
+test('an expired file does not excuse a live one that is still out of reach', function () {
+    $expired = uploadNamedFile($this->admin, 'was-current');
+    shareFileWithGroup($expired, $this->strangerGroup);
+    $expired->update(['expires_at' => now()->subDay()]);
+
+    // $this->secret is live, shared with the same group and outside this
+    // rep's library — the guard still has to answer no.
+    $this->actingAs($this->rep)
+        ->post("/groups/{$this->strangerGroup->id}/members", ['user_id' => $this->mine->id])
+        ->assertForbidden();
+});
+
 
 /**
  * The rep role ships without delete_groups, and these cases are about the