diff --git a/platforms/_registry.yml b/platforms/_registry.yml
index 970a060e..e2a8c722 100644
--- a/platforms/_registry.yml
+++ b/platforms/_registry.yml
@@ -625,6 +625,8 @@ platforms:
     source_url: https://raw.githubusercontent.com/RetroBat-Official/emulatorlauncher/master/batocera-systems/Resources/batocera-systems.json
     source_format: json
     hash_type: md5
+    # Windows: names differing only by case land on one file.
+    case_insensitive_fs: true
     schedule: weekly
     cores:
     - '81'
@@ -812,6 +814,8 @@ platforms:
     source_wiki: https://raw.githubusercontent.com/EmuDeck/emudeck.github.io/main/docs/tables/
     source_format: bash_script+csv
     hash_type: md5
+    # Windows: names differing only by case land on one file.
+    case_insensitive_fs: true
     schedule: weekly
     target_scraper: emudeck_targets
     target_source: https://github.com/dragoonDorise/EmuDeck
@@ -976,6 +980,8 @@ platforms:
     source_url: https://raw.githubusercontent.com/TASEmulators/BizHawk/master/src/BizHawk.Emulation.Common/Database/FirmwareDatabase.cs
     source_format: csharp_firmware_database
     hash_type: sha1
+    # Windows: names differing only by case land on one file.
+    case_insensitive_fs: true
     schedule: monthly
     cores:
     - applewin
diff --git a/tests/test_case_insensitive_platforms.py b/tests/test_case_insensitive_platforms.py
new file mode 100644
index 00000000..575aac27
--- /dev/null
+++ b/tests/test_case_insensitive_platforms.py
@@ -0,0 +1,34 @@
+"""A platform the installer targets on Windows or macOS packs case-insensitively.
+
+RetroBat shipped quasi88/N88.ROM (the md5 it pins) beside quasi88/n88.rom;
+extracted on NTFS the second overwrote the first and RetroBat's own check
+went red. The flag lived in retrobat.yml and vanished at the next scrape.
+"""
+
+from __future__ import annotations
+
+import sys
+import unittest
+from pathlib import Path
+
+import yaml
+
+REPO_ROOT = Path(__file__).resolve().parents[1]
+sys.path.insert(0, str(REPO_ROOT / "scripts"))
+
+
+class CaseInsensitiveWhereTheFilesystemIs(unittest.TestCase):
+    def test_windows_and_macos_platforms_carry_the_flag(self):
+        from common import load_platform_config
+
+        registry = yaml.safe_load((REPO_ROOT / "platforms" / "_registry.yml").read_text())
+        for name, data in registry["platforms"].items():
+            systems = {str(d.get("os")) for d in (data.get("install") or {}).get("detect", [])}
+            if systems & {"windows", "darwin"}:
+                with self.subTest(platform=name):
+                    config = load_platform_config(name, str(REPO_ROOT / "platforms"))
+                    self.assertTrue(config.get("case_insensitive_fs"))
+
+
+if __name__ == "__main__":
+    unittest.main()