diff --git a/Makefile b/Makefile
index 45abb20..8ea9db2 100644
--- a/Makefile
+++ b/Makefile
@@ -111,6 +111,7 @@ check:
 export-windows:
 	mkdir -p build/windows
 	$(GODOT) --headless --path . --export-release "Windows Desktop"
+	$(MAKE) test-exported-opening
 
 # Pixel cutaway: interactive disposable inn, capture and input regression.
 .PHONY: preview-pixel capture-pixel test-pixel-ui
@@ -187,3 +188,9 @@ test-stairs:
 test-transport-comparison:
 	$(GODOT) --headless --path . --script res://tests/transport/test_transport_comparison.gd
 	$(GODOT) --headless --path . --script res://tests/transport/test_runtime_transport_comparison.gd
+
+# Check the actual shipped data outside this checkout, including first build.
+WINDOWS_PCK ?= build/windows/TheTree.pck
+.PHONY: test-exported-opening
+test-exported-opening:
+	python3 tools/verify_exported_opening.py "$(WINDOWS_PCK)" --godot "$(GODOT)"
diff --git a/docs/qa/WINDOWS_RECEPTION_EXPORT_FIX.md b/docs/qa/WINDOWS_RECEPTION_EXPORT_FIX.md
new file mode 100644
index 0000000..1fe4a54
--- /dev/null
+++ b/docs/qa/WINDOWS_RECEPTION_EXPORT_FIX.md
@@ -0,0 +1,26 @@
+# Windows配布版で建築候補が空になる問題
+
+対象: 最初のWindows配布 `fb4ad23`。受付が建築候補に現れず開業できないという報告を、配布済みPCKで再現した。
+
+## 原因と修正
+
+GodotのRelease出力ではFacilityの `.tres` が `.res` に変換され、元のパスは `.remap` を通して読み込まれる。DefinitionRegistryが `FileAccess.file_exists` で元の物理ファイルを調べていたため、全18施設を `resource_not_found` として除外していた。リソースの存在判定を `ResourceLoader.exists` に変更し、既存の型・内容・IDの検証は維持した。
+
+制作フォルダーからPCKを実行すると、物理ファイルがローカルにあるため不具合が隠れる。前回の単なる起動smokeでも候補の欠落は検出できなかった。
+
+## 検証
+
+- 制作フォルダー外の一時ディレクトリで、配布済みPCKだけを起動。`FileAccess=false / ResourceLoader=true` を確認し、18施設の欠落・パレット空を再現。
+- 修正版PCKを同じ隔離条件で起動し、13項目成功。制作ファイルへのフォールバックなし、全18施設、受付ボタンの表示・選択、初日ガイドからの選択、マップ配置、500Gの支払い、120分後の完成、客室建設への案内を確認。
+- macOS版Godotによる配布PCKの実描画で受付完成と建築候補を確認。Windows実機での再検証は未実施。
+- DefinitionRegistryの既存266項目が成功し、存在しないデータの拒否も維持。
+
+`make export-windows` は以後、書き出し後に隔離した実建設チェックを実行する。既存PCKの検証は次のコマンドで行える。
+
+```
+make test-exported-opening WINDOWS_PCK=/absolute/path/TheTree.pck
+```
+
+`tools/verify_exported_opening.py` が一時ディレクトリから `tests/export/test_exported_opening.gd` を実行する。試験では保存を無効にし、実際の建設UIとCommandを使う。制作ファイルが見つかった場合も失敗させる。
+
+証跡: `artifacts/windows-opening-before-isolated.log`、`windows-opening-fixed-visual.log`、`windows-registry-fix.log`、`windows-reception-fixed.png`。修正版配布は `build/windows/TheTree-Windows-reception-fix.zip`。EXEとPCKを含めて全体を展開し、新しいフォルダーから起動する。
diff --git a/scripts/core/definition_registry.gd b/scripts/core/definition_registry.gd
index ca7bdbc..7b8fea3 100644
--- a/scripts/core/definition_registry.gd
+++ b/scripts/core/definition_registry.gd
@@ -266,7 +266,9 @@ func _validate_requested_path(path: String) -> bool:
 			"Facility definitions must use the .tres extension."
 		)
 		valid = false
-	if not FileAccess.file_exists(path):
+	# Exported .tres resources are remapped to binary .res files. Physical
+	# FileAccess checks incorrectly reject them when no source checkout exists.
+	if not ResourceLoader.exists(path):
 		_add_error(
 			&"resource_not_found",
 			&"",
diff --git a/tests/export/test_exported_opening.gd b/tests/export/test_exported_opening.gd
new file mode 100644
index 0000000..38fa63a
--- /dev/null
+++ b/tests/export/test_exported_opening.gd
@@ -0,0 +1,67 @@
+extends SceneTree
+
+## Run against the distributed pack, not the source checkout:
+## godot --headless --main-pack /absolute/TheTree.pck --script /absolute/this_script.gd
+var _failures := 0
+var _checks := 0
+
+func _initialize() -> void:
+	call_deferred("_run")
+
+func _run() -> void:
+	var runtime: Variant = root.get_node("SimulationRuntime")
+	var clock: Variant = root.get_node("GameClock")
+	clock.set_paused(true)
+	runtime.configure_save_policy({&"enabled": false, &"daily_checkpoint_enabled": false})
+	if OS.get_environment("THE_TREE_REQUIRE_EXPORTED") == "1":
+		_expect(not FileAccess.file_exists("res://project.godot") and not FileAccess.file_exists("res://data/facilities/reception.tres"), "release regression has no source checkout fallback")
+	print("RECEPTION_RESOURCE file=%s resource=%s" % [FileAccess.file_exists("res://data/facilities/reception.tres"), ResourceLoader.exists("res://data/facilities/reception.tres")])
+	_expect(runtime.definition_registry.is_valid(), "exported facility definitions validate: %s" % runtime.definition_registry.get_report())
+	_expect(runtime.definition_registry.facility_count() == 18, "all 18 buildable definitions are present in the shipped pack")
+	var main: Control = load("res://scenes/main/main.tscn").instantiate()
+	root.add_child(main)
+	runtime.configure_save_policy({&"enabled": false, &"daily_checkpoint_enabled": false})
+	await process_frame
+	await process_frame
+	var buttons: Dictionary = main.get("build_buttons")
+	_expect(buttons.size() == 18, "the actual build palette exposes all 18 facilities")
+	_expect(buttons.has(&"reception"), "reception is selectable in the actual build palette")
+	if not buttons.has(&"reception"):
+		_finish()
+		return
+	_expect("受付" in buttons[&"reception"].text and not buttons[&"reception"].disabled, "reception button is labeled and enabled")
+	var guide: Variant = main.find_child("InnOpeningGuide", true, false)
+	_expect(guide != null and guide.get_progress().get(&"action") == &"build_reception", "new-game guide offers reception construction")
+	if guide != null:
+		(guide.get("_action") as Button).pressed.emit()
+	await process_frame
+	_expect(main.get("palette_scroll").visible and buttons[&"reception"].is_visible_in_tree(), "guide action opens the palette with a visible reception button")
+	buttons[&"reception"].button_pressed = false
+	buttons[&"reception"].button_pressed = true
+	_expect(main.get("_selected_definition_id") == &"reception", "the reception button selects the real construction tool")
+	main.call("_on_map_cell_clicked", Vector3i(-8, 0, 0))
+	_expect(runtime.construction_service.get_jobs().size() == 1, "map placement starts one real reception construction job")
+	_expect(runtime.economy_service.get_balance(&"PLAYER_CASH") == 4500, "reception construction charges the actual 500 G cost")
+	clock.advance_minutes(120)
+	var reception: Variant = null
+	for facility: Variant in runtime.facility_service.get_instances():
+		if facility.definition_id == &"reception":
+			reception = facility
+	_expect(reception != null, "the reception completes from the exported game data")
+	_expect(guide != null and guide.get_progress().get(&"stage") == &"room", "opening guide advances to building a room")
+	if OS.get_environment("THE_TREE_EXPORT_CAPTURE") == "1":
+		main.call("_refresh_dashboard")
+		await process_frame
+		await RenderingServer.frame_post_draw
+		root.get_texture().get_image().save_png(OS.get_environment("THE_TREE_EXPORT_CAPTURE_PATH"))
+	_finish()
+
+func _expect(ok: bool, label: String) -> void:
+	_checks += 1
+	if not ok:
+		_failures += 1
+	print("%s: %s" % ["PASS" if ok else "FAIL", label])
+
+func _finish() -> void:
+	print("Exported opening: %d checks, %d failures" % [_checks, _failures])
+	quit(1 if _failures else 0)
diff --git a/tools/verify_exported_opening.py b/tools/verify_exported_opening.py
new file mode 100644
index 0000000..811cd77
--- /dev/null
+++ b/tools/verify_exported_opening.py
@@ -0,0 +1,39 @@
+#!/usr/bin/env python3
+"""Exercise the distributed PCK with no source-tree fallback or player saves."""
+import argparse
+import os
+from pathlib import Path
+import shutil
+import subprocess
+import tempfile
+
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("pack", type=Path)
+    parser.add_argument("--godot", default="godot")
+    parser.add_argument("--capture", type=Path)
+    args = parser.parse_args()
+    pack = args.pack.resolve(strict=True)
+    godot = shutil.which(args.godot)
+    if godot is None:
+        parser.error(f"Godot executable not found: {args.godot}")
+    script = Path(__file__).resolve().parents[1] / "tests/export/test_exported_opening.gd"
+    env = dict(os.environ, THE_TREE_REQUIRE_EXPORTED="1")
+    command = [godot]
+    if args.capture:
+        output = args.capture.resolve()
+        output.parent.mkdir(parents=True, exist_ok=True)
+        env.update(THE_TREE_EXPORT_CAPTURE="1", THE_TREE_EXPORT_CAPTURE_PATH=str(output))
+    else:
+        command.append("--headless")
+    command.extend(["--main-pack", str(pack), "--script", str(script)])
+    # Running inside the checkout masks missing packed resources: FileAccess
+    # can read original .tres files from disk even when the PCK only has .remap.
+    with tempfile.TemporaryDirectory(prefix="the-tree-export-check-") as isolated:
+        result = subprocess.run(command, cwd=isolated, env=env, timeout=180)
+    return result.returncode
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())