diff --git a/__init__.py b/__init__.py
index aa7acc6..e33aa42 100644
--- a/__init__.py
+++ b/__init__.py
@@ -151,6 +151,8 @@ __all__ = ["NODE_CLASS_MAPPINGS", "NODE_DISPLAY_NAME_MAPPINGS", "WEB_DIRECTORY"]
 print()
 print(f"\033[94m[ComfyUI-PromptManager] Version:\033[0m {get_version()}")
 for node_key, display_name in NODE_DISPLAY_NAME_MAPPINGS.items():
-    print(f"🫶 \033[94mLoaded:\033[0m {display_name}")
+    # ASCII only: a Windows console using a legacy code page cannot print emoji,
+    # and a UnicodeEncodeError here would abort loading the whole node.
+    print(f"  \033[94mLoaded:\033[0m {display_name}")
 print(f"\033[94mTotal: {len(NODE_CLASS_MAPPINGS)} tools loaded\033[0m")
 print()
diff --git a/database/models.py b/database/models.py
index 3c1d4c7..351835d 100644
--- a/database/models.py
+++ b/database/models.py
@@ -8,6 +8,8 @@ import shutil
 import sqlite3
 import os
 import threading
+import weakref
+from contextlib import closing
 from pathlib import Path
 from typing import Set, Tuple
 
@@ -59,6 +61,10 @@ class PromptModel:
     # same file; only the first one pays for the schema check.
     _initialized_paths: Set[str] = set()
     _init_lock = threading.Lock()
+    # Every live model, so a shutdown or a test teardown can close them all
+    # before the database file is deleted (Windows refuses otherwise).
+    _instances: "weakref.WeakSet[PromptModel]" = weakref.WeakSet()
+    _instances_lock = threading.Lock()
 
     def __init__(self, db_path: str):
         """
@@ -78,6 +84,8 @@ class PromptModel:
         # Bumped by _close_all_connections so threads holding a closed
         # connection reopen on their next get_connection().
         self._generation = 0
+        with PromptModel._instances_lock:
+            PromptModel._instances.add(self)
         self._ensure_database_exists()
 
     def _ensure_database_exists(self) -> None:
@@ -292,6 +300,14 @@ class PromptModel:
             self._connections.add(conn)
         return conn
 
+    @classmethod
+    def close_all_instances(cls) -> None:
+        """Close every connection of every live model in this process."""
+        with cls._instances_lock:
+            models = list(cls._instances)
+        for model in models:
+            model.close_all()
+
     def close_all(self) -> None:
         """Close every thread's connection; they reopen lazily on next use.
 
@@ -627,7 +643,7 @@ class PromptModel:
         improving query performance and reducing file size.
         """
         try:
-            with sqlite3.connect(self.db_path) as conn:
+            with closing(sqlite3.connect(self.db_path)) as conn:
                 conn.execute("VACUUM")
                 conn.commit()
         except Exception as e:
diff --git a/database/operations.py b/database/operations.py
index 879c56c..f942a18 100644
--- a/database/operations.py
+++ b/database/operations.py
@@ -89,7 +89,7 @@ def _resolve_db_path(db_path: Optional[str] = None) -> str:
             db_path = "prompts.db"
 
     if not os.path.isabs(db_path):
-        db_path = os.path.join(extension_root, db_path)
+        db_path = os.path.normpath(os.path.join(extension_root, db_path))
 
     # Ensure parent directory exists for custom paths
     parent = os.path.dirname(db_path)
@@ -165,6 +165,11 @@ class PromptDatabase:
         """Close the calling thread's database connection (see PromptModel.close)."""
         self.model.close()
 
+    @staticmethod
+    def close_all_instances() -> None:
+        """Close the connections of every PromptDatabase/PromptModel in the process."""
+        PromptModel.close_all_instances()
+
     def close_all(self) -> None:
         """Close every thread's connection (see PromptModel.close_all)."""
         self.model.close_all()
@@ -667,7 +672,8 @@ class PromptDatabase:
                             rel = os.path.relpath(parent, root)
                             if not rel.startswith(".."):
                                 if rel != ".":
-                                    folders.add(rel)
+                                    # Clients split and filter on "/" whatever the OS
+                                    folders.add(rel.replace(os.sep, "/"))
                                 made_relative = True
                                 break
                         except ValueError:
diff --git a/py/api/admin.py b/py/api/admin.py
index 5727c30..6a92dc4 100644
--- a/py/api/admin.py
+++ b/py/api/admin.py
@@ -2,6 +2,7 @@
 
 import asyncio
 import contextlib
+from contextlib import closing
 import datetime
 import hashlib
 import json
@@ -190,7 +191,7 @@ def _diagnose_database(db_path):
             "message": f"Database file not found: {os.path.basename(db_path)}",
         }
     try:
-        with sqlite3.connect(db_path) as conn:
+        with closing(sqlite3.connect(db_path)) as conn:
             prompt_count = conn.execute("SELECT COUNT(*) FROM prompts").fetchone()[0]
             has_images_table = (
                 conn.execute(
@@ -1219,7 +1220,10 @@ class AdminRoutesMixin:
             removed = await self._run_in_executor(_prune_safety_backups, model.db_path)
             if removed:
                 self.logger.info(f"Removed {len(removed)} old safety backups")
+            previous = self.db
             self.db = PromptDatabase(model.db_path)
+            # Its connections would otherwise linger (a file lock on Windows)
+            previous.close_all()
             prompt_count = self.db.model.get_database_info().get("total_prompts", 0)
 
             return web.json_response(
diff --git a/requirements-dev.txt b/requirements-dev.txt
index 9acf917..7338347 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -5,6 +5,7 @@ aiohttp>=3.8.0
 
 # Tests and coverage
 coverage>=7.0
+numpy>=1.24  # WD14 engine tests
 
 # Code quality
 black>=24.0.0
diff --git a/tests/open_handles.py b/tests/open_handles.py
new file mode 100644
index 0000000..fef1d86
--- /dev/null
+++ b/tests/open_handles.py
@@ -0,0 +1,43 @@
+"""Teardown guard: fail when a file about to be deleted is still open.
+
+Windows refuses to delete an open file, so a sqlite connection that was not
+closed explicitly turns into a PermissionError in CI there. Linux would let
+the deletion through silently; this check makes the Linux run catch the same
+mistake. It inspects /proc/self/fd and is a no-op where that does not exist.
+"""
+
+import os
+
+
+def open_handles_under(path):
+    """Basenames of this process's open files at *path* or below it."""
+    fd_dir = "/proc/self/fd"
+    if not os.path.isdir(fd_dir):
+        return []
+    real = os.path.realpath(str(path))
+    hits = []
+    for fd in os.listdir(fd_dir):
+        try:
+            target = os.readlink(os.path.join(fd_dir, fd))
+        except OSError:
+            continue
+        if not target.startswith(os.sep):
+            continue  # sockets, pipes, anon inodes
+        target = target.replace(" (deleted)", "")
+        if (
+            target == real
+            or target.startswith(real + os.sep)
+            or target.startswith(real + "-")
+        ):
+            hits.append(os.path.basename(target))
+    return sorted(hits)
+
+
+def assert_closed(testcase, *paths):
+    """Fail *testcase* if any of *paths* (files or directories) is still open."""
+    hits = [hit for path in paths for hit in open_handles_under(path)]
+    if hits:
+        testcase.fail(
+            "Files still open at teardown (Windows could not delete them): "
+            + ", ".join(hits)
+        )
diff --git a/tests/test_api_admin.py b/tests/test_api_admin.py
index 340ea53..fdb2d1b 100644
--- a/tests/test_api_admin.py
+++ b/tests/test_api_admin.py
@@ -20,6 +20,12 @@ _mock_server.PromptServer.instance.routes = MagicMock()
 sys.modules.setdefault("server", _mock_server)
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+from database.models import PromptModel  # noqa: E402
+
+try:
+    from tests.open_handles import assert_closed  # noqa: E402
+except ImportError:  # discovered with tests/ as the top-level directory
+    from open_handles import assert_closed  # noqa: E402
 
 from aiohttp import web  # noqa: E402
 from aiohttp.test_utils import AioHTTPTestCase  # noqa: E402
@@ -36,7 +42,9 @@ class AdminAPITestCase(AioHTTPTestCase):
     """Test app with PromptManager routes, temp DB and config, fake ComfyUI tree."""
 
     async def get_application(self):
-        self.tmpdir = tempfile.mkdtemp()
+        # realpath: macOS hands out /var/... for a /private/var/... directory and
+        # the gallery roots are stored resolved
+        self.tmpdir = os.path.realpath(tempfile.mkdtemp())
         self.comfy_dir = Path(self.tmpdir) / "ComfyUI"
         self.output_dir = self.comfy_dir / "output"
         self.output_dir.mkdir(parents=True)
@@ -81,7 +89,8 @@ class AdminAPITestCase(AioHTTPTestCase):
             sys.modules.pop("folder_paths", None)
         else:
             sys.modules["folder_paths"] = self._orig_folder_paths
-        self.api.db.close_all()
+        PromptModel.close_all_instances()  # restore may have swapped api.db
+        assert_closed(self, self.tmpdir)
         shutil.rmtree(self.tmpdir, ignore_errors=True)
 
     # ── helpers ────────────────────────────────────────────────────────
diff --git a/tests/test_api_backup_restore.py b/tests/test_api_backup_restore.py
index 326537a..fb473d9 100644
--- a/tests/test_api_backup_restore.py
+++ b/tests/test_api_backup_restore.py
@@ -14,6 +14,12 @@ import unittest
 from unittest.mock import patch
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+from database.models import PromptModel  # noqa: E402
+
+try:
+    from tests.open_handles import assert_closed  # noqa: E402
+except ImportError:  # discovered with tests/ as the top-level directory
+    from open_handles import assert_closed  # noqa: E402
 
 import aiohttp
 from aiohttp import web
@@ -47,7 +53,8 @@ class BackupRestoreTestCase(AioHTTPTestCase):
 
     async def tearDownAsync(self):
         await super().tearDownAsync()  # closes the aiohttp test client
-        self.api.db.close_all()
+        PromptModel.close_all_instances()  # restore may have swapped api.db
+        assert_closed(self, self.tmpdir)
         for name in os.listdir(self.tmpdir):
             os.unlink(os.path.join(self.tmpdir, name))
         os.rmdir(self.tmpdir)
diff --git a/tests/test_api_core.py b/tests/test_api_core.py
index 1008cce..16d4a55 100644
--- a/tests/test_api_core.py
+++ b/tests/test_api_core.py
@@ -16,6 +16,12 @@ sys.modules.setdefault("server", _mock_server)
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
+try:
+    from tests.open_handles import assert_closed  # noqa: E402
+except ImportError:  # discovered with tests/ as the top-level directory
+    from open_handles import assert_closed  # noqa: E402
+from database.models import PromptModel  # noqa: E402
+
 from aiohttp import web  # noqa: E402
 from aiohttp.test_utils import AioHTTPTestCase  # noqa: E402
 
@@ -33,6 +39,8 @@ class FolderPathsFixture(unittest.TestCase):
     def setUp(self):
         self.tmpdir = tempfile.mkdtemp()
         self.addCleanup(shutil.rmtree, self.tmpdir, True)
+        self.addCleanup(assert_closed, self, self.tmpdir)  # just before the rmtree
+        self.addCleanup(PromptModel.close_all_instances)
         self.comfy_dir = Path(self.tmpdir) / "ComfyUI"
         self.output_dir = self.comfy_dir / "output"
         self.output_dir.mkdir(parents=True)
diff --git a/tests/test_api_images.py b/tests/test_api_images.py
index b52437d..7c77e31 100644
--- a/tests/test_api_images.py
+++ b/tests/test_api_images.py
@@ -213,6 +213,8 @@ class TestServeOutputImage(ImageAPITestCase):
             self.assertEqual(hit.status, 200)
             self.assertEqual(miss.status, 404)
             self.assertEqual(bad_index.status, 200)
+            for resp in (hit, miss, bad_index):
+                await resp.read()  # release the served file before the directory goes
 
 
 class TestServeImageById(ImageAPITestCase):
@@ -1269,6 +1271,7 @@ class TestLoraManagerPathAllowList(ImageRouteCoverageCase):
                 "GET", f"/prompt_manager/images/{image_id}/file"
             )
             self.assertEqual(resp.status, 200)
+            await resp.read()  # release the served file before the directory goes
             resolve.assert_called_once_with(configured)
 
 
diff --git a/tests/test_api_logging.py b/tests/test_api_logging.py
index 1614909..cf15f96 100644
--- a/tests/test_api_logging.py
+++ b/tests/test_api_logging.py
@@ -348,7 +348,7 @@ class TestLogFilesAndDownload(LoggingAPITestCase):
         self.assertEqual(data["files"], [])
 
     async def test_download_existing_file(self):
-        (self.log_dir / "prompt_manager.log").write_text("line1\nline2\n")
+        (self.log_dir / "prompt_manager.log").write_bytes(b"line1\nline2\n")
 
         resp = await self.client.request(
             "GET", "/prompt_manager/logs/download/prompt_manager.log"
diff --git a/tests/test_basic.py b/tests/test_basic.py
index ca70b02..7545848 100644
--- a/tests/test_basic.py
+++ b/tests/test_basic.py
@@ -12,6 +12,11 @@ import sys
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
+try:
+    from tests.open_handles import assert_closed  # noqa: E402
+except ImportError:  # discovered with tests/ as the top-level directory
+    from open_handles import assert_closed  # noqa: E402
+
 from database.operations import PromptDatabase
 from utils.hashing import generate_prompt_hash
 from utils.validators import validate_prompt_text, validate_rating, validate_tags
@@ -30,8 +35,12 @@ class TestBasicFunctionality(unittest.TestCase):
     def tearDown(self):
         """Clean up test fixtures."""
         # Remove temporary database
-        if os.path.exists(self.temp_db.name):
-            os.unlink(self.temp_db.name)
+        if getattr(self, "db", None) is not None:
+            self.db.close_all()
+        assert_closed(self, self.temp_db.name)
+        for suffix in ("", "-wal", "-shm"):
+            if os.path.exists(self.temp_db.name + suffix):
+                os.unlink(self.temp_db.name + suffix)
 
     def test_prompt_hash_generation(self):
         """Test prompt hash generation."""
@@ -214,8 +223,12 @@ class TestNodeIntegration(unittest.TestCase):
     def tearDown(self):
         """Clean up test fixtures."""
         # Remove temporary database
-        if os.path.exists(self.temp_db.name):
-            os.unlink(self.temp_db.name)
+        if getattr(self, "db", None) is not None:
+            self.db.close_all()
+        assert_closed(self, self.temp_db.name)
+        for suffix in ("", "-wal", "-shm"):
+            if os.path.exists(self.temp_db.name + suffix):
+                os.unlink(self.temp_db.name + suffix)
 
     @patch("prompt_manager_base.PromptDatabase")
     def test_node_encode_function(self, mock_db_class):
diff --git a/tests/test_database.py b/tests/test_database.py
index cd64f6a..b33d233 100644
--- a/tests/test_database.py
+++ b/tests/test_database.py
@@ -10,6 +10,7 @@ import csv
 import json
 import os
 import sqlite3
+from contextlib import closing
 import sys
 import tempfile
 import types
@@ -17,6 +18,12 @@ import unittest
 from unittest.mock import MagicMock, patch
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+from database.models import PromptModel  # noqa: E402
+
+try:
+    from tests.open_handles import assert_closed  # noqa: E402
+except ImportError:  # discovered with tests/ as the top-level directory
+    from open_handles import assert_closed  # noqa: E402
 
 from database.operations import PromptDatabase, _resolve_db_path
 from utils.hashing import generate_prompt_hash
@@ -31,7 +38,8 @@ class DatabaseTestCase(unittest.TestCase):
         self.db = PromptDatabase(self.temp_db.name)
 
     def tearDown(self):
-        self.db.close_all()
+        PromptModel.close_all_instances()
+        assert_closed(self, self.temp_db.name)
         for suffix in ("", "-wal", "-shm"):
             path = self.temp_db.name + suffix
             if os.path.exists(path):
@@ -756,7 +764,7 @@ class TestExport(DatabaseTestCase):
 class TestDuplicateMerging(DatabaseTestCase):
     def _save_dup(self, text, created_at, **kwargs):
         pid = self.db.save_prompt(text=text, prompt_hash=None, **kwargs)
-        with sqlite3.connect(self.temp_db.name) as conn:
+        with closing(sqlite3.connect(self.temp_db.name)) as conn, conn:
             conn.execute(
                 "UPDATE prompts SET created_at = ? WHERE id = ?", (created_at, pid)
             )
@@ -852,7 +860,7 @@ class TestImageQueries(DatabaseTestCase):
         b = self._save("beta prompt")
         self.db.link_image_to_prompt(a, "/out/a1.png")
         self.db.link_image_to_prompt(b, "/out/b1.png")
-        with sqlite3.connect(self.temp_db.name) as conn:
+        with closing(sqlite3.connect(self.temp_db.name)) as conn, conn:
             conn.execute(
                 "UPDATE generated_images SET generation_time = '2026-01-01 00:00:00'"
                 " WHERE filename = 'a1.png'"
@@ -938,7 +946,7 @@ class TestImageQueries(DatabaseTestCase):
     def test_image_row_with_broken_json_yields_empty_dicts(self):
         pid = self._save("broken")
         image_id = self.db.link_image_to_prompt(pid, "/out/broken.png")
-        with sqlite3.connect(self.temp_db.name) as conn:
+        with closing(sqlite3.connect(self.temp_db.name)) as conn, conn:
             conn.execute(
                 "UPDATE generated_images SET workflow_data = '{not json', "
                 "prompt_metadata = '{\"k\": 1}', parameters = NULL WHERE id = ?",
@@ -1027,7 +1035,7 @@ class TestMaintenanceOperations(DatabaseTestCase):
         pid = self._save("to orphan", tags=["t"])
         self.db.link_image_to_prompt(pid, "/out/o.png")
         self.db.close()
-        with sqlite3.connect(self.temp_db.name) as conn:
+        with closing(sqlite3.connect(self.temp_db.name)) as conn, conn:
             conn.execute("PRAGMA foreign_keys = OFF")
             conn.execute("DELETE FROM prompts WHERE id = ?", (pid,))
 
@@ -1139,7 +1147,7 @@ class TestRowConversion(DatabaseTestCase):
 
     def test_search_date_filters(self):
         pid = self._save("dated")
-        with sqlite3.connect(self.temp_db.name) as conn:
+        with closing(sqlite3.connect(self.temp_db.name)) as conn, conn:
             conn.execute(
                 "UPDATE prompts SET created_at = '2026-05-01T00:00:00' WHERE id = ?",
                 (pid,),
diff --git a/tests/test_database_migrations.py b/tests/test_database_migrations.py
index 467aa69..73b8011 100644
--- a/tests/test_database_migrations.py
+++ b/tests/test_database_migrations.py
@@ -16,6 +16,7 @@ sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
 from database.models import PromptModel
 from database.operations import PromptDatabase
+from database.models import normalize_image_path  # noqa: E402
 
 LEGACY_PROMPTS_TABLE = (
     "CREATE TABLE prompts (id INTEGER PRIMARY KEY AUTOINCREMENT,"
@@ -260,7 +261,7 @@ class TestIdempotentMigrations(MigrationTestCase):
         self.assertEqual(
             sorted(i["file_path"] for i in images),
             sorted(
-                os.path.normcase(os.path.normpath(p))
+                normalize_image_path(p)
                 for p in (
                     "/out/2026-01-01/a.png",
                     "/out/2026-01-02/a.png",
diff --git a/tests/test_diagnostics_config.py b/tests/test_diagnostics_config.py
index 9ecf077..fdbd9c3 100644
--- a/tests/test_diagnostics_config.py
+++ b/tests/test_diagnostics_config.py
@@ -10,6 +10,7 @@ Verifies that:
 import asyncio
 import json
 import os
+from contextlib import closing
 import sys
 import tempfile
 import types
@@ -119,7 +120,7 @@ class TestAdminEndpointsUseConfigPath(unittest.TestCase):
         try:
             import sqlite3
 
-            with sqlite3.connect(db_file) as conn:
+            with closing(sqlite3.connect(db_file)) as conn, conn:
                 conn.execute(
                     "CREATE TABLE prompts "
                     "(id INTEGER PRIMARY KEY, text TEXT, created_at TEXT)"
diff --git a/tests/test_extension_web_dir.py b/tests/test_extension_web_dir.py
index 57f371f..b360f04 100644
--- a/tests/test_extension_web_dir.py
+++ b/tests/test_extension_web_dir.py
@@ -14,7 +14,7 @@ ROOT = os.path.dirname(TESTS_DIR)
 sys.path.insert(0, ROOT)
 sys.path.insert(0, TESTS_DIR)
 
-from test_init_package import load_package  # noqa: E402
+from test_init_package import close_every_database, load_package  # noqa: E402
 
 
 class TestExtensionWebDir(unittest.TestCase):
@@ -35,6 +35,7 @@ class TestExtensionWebDir(unittest.TestCase):
         if monitor is not None:
             monitor.stop_monitoring()
         sys.modules.pop(cls.package_name, None)
+        close_every_database()  # the package's database must not hold the temp dir open
         cls.tmp.cleanup()
 
     def test_web_directory_is_the_canvas_extension_folder(self):
diff --git a/tests/test_init_package.py b/tests/test_init_package.py
index b25ee28..b10870a 100644
--- a/tests/test_init_package.py
+++ b/tests/test_init_package.py
@@ -17,6 +17,11 @@ from aiohttp import web
 ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
 sys.path.insert(0, ROOT)
 
+try:
+    from tests.open_handles import open_handles_under  # noqa: E402
+except ImportError:  # discovered with tests/ as the top-level directory
+    from open_handles import open_handles_under  # noqa: E402
+
 
 class FakePromptQueue:
     def __init__(self):
@@ -82,6 +87,17 @@ def load_package(name, db_path, output_dir, server=None):
     return package, server.PromptServer.instance
 
 
+def close_every_database():
+    """Close connections of every PromptModel registry in the process.
+
+    A package loaded under its own name imports its own copy of
+    database.models, whose PromptModel class keeps its own registry.
+    """
+    for name, module in list(sys.modules.items()):
+        if name.endswith("database.models") and hasattr(module, "PromptModel"):
+            module.PromptModel.close_all_instances()
+
+
 class PackageTestCase(unittest.TestCase):
     package_name = "prompt_manager_pkg"
 
@@ -109,7 +125,10 @@ class PackageTestCase(unittest.TestCase):
         if monitor is not None:
             monitor.stop_monitoring()
         sys.modules.pop(cls.package_name, None)
+        close_every_database()
+        hits = open_handles_under(cls.tmp.name)
         cls.tmp.cleanup()
+        assert not hits, f"files still open before temp dir cleanup: {hits}"
 
 
 class TestPackageWiring(PackageTestCase):
@@ -220,3 +239,30 @@ class TestPackageWhenHookRegistrationFails(PackageTestCase):
 
 if __name__ == "__main__":
     unittest.main()
+
+
+class TestConsoleBanner(unittest.TestCase):
+    """Loading the node must not depend on the console being able to print emoji."""
+
+    def test_package_loads_with_a_cp1252_console(self):
+        import contextlib
+        import io
+
+        tmp = tempfile.TemporaryDirectory()
+        self.addCleanup(tmp.cleanup)
+        self.addCleanup(close_every_database)
+        output_dir = os.path.join(tmp.name, "output")
+        os.makedirs(output_dir)
+        name = "prompt_manager_pkg_cp1252"
+        stream = io.TextIOWrapper(io.BytesIO(), encoding="cp1252", errors="strict")
+
+        with contextlib.redirect_stdout(stream):
+            package, _ = load_package(name, os.path.join(tmp.name, "p.db"), output_dir)
+        self.addCleanup(sys.modules.pop, name, None)
+        monitor = getattr(package, "_global_image_monitor", None)
+        if monitor is not None:
+            self.addCleanup(monitor.stop_monitoring)
+
+        stream.flush()
+        banner = stream.buffer.getvalue().decode("cp1252")
+        self.assertIn("Loaded:", banner)
diff --git a/tests/test_lora_database.py b/tests/test_lora_database.py
index 5be8c9a..648b821 100644
--- a/tests/test_lora_database.py
+++ b/tests/test_lora_database.py
@@ -195,6 +195,25 @@ class TestGetPromptSubfolders(LoraDBTestCase):
         self.assertIsInstance(folders, list)
         self.assertGreater(len(folders), 0)
 
+    def test_subfolders_use_forward_slashes_on_every_platform(self):
+        """Clients split folders on "/" whatever separator the OS produced."""
+        from unittest import mock
+
+        import database.operations as operations
+
+        pid = self._save("prompt")
+        self._link_image(pid, "/output/2026/08-Aug/06/img.png")
+
+        with (
+            mock.patch.object(
+                operations.os.path, "relpath", return_value="2026\\08-Aug\\06"
+            ),
+            mock.patch.object(operations.os, "sep", "\\"),
+        ):
+            folders = self.db.get_prompt_subfolders(root_dirs=["/output"])
+
+        self.assertEqual(folders, ["2026/08-Aug/06"])
+
     def test_include_ancestors_adds_intermediate_paths(self):
         pid = self._save("prompt")
         self._link_image(pid, "/output/2026/08-Aug/2026-08-06/img.png")
diff --git a/tests/test_lora_utils.py b/tests/test_lora_utils.py
index 61ab15b..b273643 100644
--- a/tests/test_lora_utils.py
+++ b/tests/test_lora_utils.py
@@ -229,7 +229,7 @@ class TestGetLoraImageCacheDir(unittest.TestCase):
     def test_returns_path(self):
         cache_dir = get_lora_image_cache_dir()
         self.assertIsInstance(cache_dir, Path)
-        self.assertTrue(str(cache_dir).endswith("data/lora_images"))
+        self.assertEqual(cache_dir.parts[-2:], ("data", "lora_images"))
 
     def test_directory_exists(self):
         cache_dir = get_lora_image_cache_dir()
diff --git a/tests/test_prompt_usage.py b/tests/test_prompt_usage.py
index fd5fa19..c460664 100644
--- a/tests/test_prompt_usage.py
+++ b/tests/test_prompt_usage.py
@@ -2,12 +2,18 @@
 
 import os
 import sqlite3
+from contextlib import closing
 import sys
 import tempfile
 import unittest
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
+try:
+    from tests.open_handles import assert_closed  # noqa: E402
+except ImportError:  # discovered with tests/ as the top-level directory
+    from open_handles import assert_closed  # noqa: E402
+
 from database.models import PromptModel
 from database.operations import PromptDatabase
 from prompt_manager_base import PromptManagerBase
@@ -23,6 +29,8 @@ class UsageTestCase(unittest.TestCase):
     def tearDown(self):
         if getattr(self, "db", None) is not None:
             self.db.close_all()
+        PromptModel.close_all_instances()
+        assert_closed(self, self.path)
         for suffix in ("", "-wal", "-shm"):
             if os.path.exists(self.path + suffix):
                 os.unlink(self.path + suffix)
@@ -33,7 +41,7 @@ class UsageTestCase(unittest.TestCase):
         )
 
     def _set(self, prompt_id, **columns):
-        with sqlite3.connect(self.path) as conn:
+        with closing(sqlite3.connect(self.path)) as conn, conn:
             for column, value in columns.items():
                 conn.execute(
                     f"UPDATE prompts SET {column} = ? WHERE id = ?", (value, prompt_id)
@@ -169,7 +177,7 @@ class TestUsageMigration(unittest.TestCase):
         self.with_images = db.save_prompt(text="has images", prompt_hash="h1")
         self.no_images = db.save_prompt(text="no images", prompt_hash="h2")
         db.close_all()
-        with sqlite3.connect(self.path) as conn:
+        with closing(sqlite3.connect(self.path)) as conn, conn:
             conn.execute(
                 "UPDATE prompts SET created_at = '2026-01-01T10:00:00.000000+00:00'"
             )
@@ -199,6 +207,8 @@ class TestUsageMigration(unittest.TestCase):
     def tearDown(self):
         for db in self.dbs:
             db.close_all()
+        PromptModel.close_all_instances()
+        assert_closed(self, self.path)
         for suffix in ("", "-wal", "-shm"):
             if os.path.exists(self.path + suffix):
                 os.unlink(self.path + suffix)
@@ -218,7 +228,7 @@ class TestUsageMigration(unittest.TestCase):
         # A row whose usage is unknown (e.g. written by 3.2.3 after a downgrade)
         # stays "never run": a restart must not invent a run for it, otherwise
         # Recently Used could never tell saved-but-unused prompts from run ones.
-        with sqlite3.connect(self.path) as conn:
+        with closing(sqlite3.connect(self.path)) as conn, conn:
             conn.execute(
                 "INSERT INTO prompts (text, hash, created_at)"
                 " VALUES ('from 3.2.3', 'h3', '2026-04-01T00:00:00.000000+00:00')"
diff --git a/tests/test_utils_diagnostics.py b/tests/test_utils_diagnostics.py
index 33353d8..c001233 100644
--- a/tests/test_utils_diagnostics.py
+++ b/tests/test_utils_diagnostics.py
@@ -3,6 +3,7 @@
 import os
 import pathlib
 import sqlite3
+from contextlib import closing
 import sys
 import tempfile
 import types
@@ -75,7 +76,7 @@ class TestDatabaseChecks(DiagnosticsTestCase):
         self.assertEqual(self.diag.check_images_table()["status"], "error")
 
     def test_database_without_images_table(self):
-        with sqlite3.connect(self.db_path) as conn:
+        with closing(sqlite3.connect(self.db_path)) as conn, conn:
             conn.execute("CREATE TABLE prompts (id INTEGER PRIMARY KEY, text TEXT)")
         self.assertEqual(
             self.diag.check_database(),
diff --git a/utils/diagnostics.py b/utils/diagnostics.py
index 14f1581..c0c72d4 100644
--- a/utils/diagnostics.py
+++ b/utils/diagnostics.py
@@ -32,6 +32,7 @@ The diagnostics provide:
 
 import os
 import sqlite3
+from contextlib import closing
 from pathlib import Path
 from typing import Dict, Any
 
@@ -147,7 +148,7 @@ class GalleryDiagnostics:
                     "message": f"Database file not found: {self.db_path}",
                 }
 
-            with sqlite3.connect(self.db_path) as conn:
+            with closing(sqlite3.connect(self.db_path)) as conn:
                 conn.row_factory = sqlite3.Row
 
                 # Check prompts table
@@ -189,7 +190,7 @@ class GalleryDiagnostics:
         self.logger.info("\n[IMG]  Checking Images Table...")
 
         try:
-            with sqlite3.connect(self.db_path) as conn:
+            with closing(sqlite3.connect(self.db_path)) as conn:
                 conn.row_factory = sqlite3.Row
 
                 # Check if table exists