diff --git a/app/igneum-app/src/config.rs b/app/igneum-app/src/config.rs
index d55883c13..214ced9e5 100644
--- a/app/igneum-app/src/config.rs
+++ b/app/igneum-app/src/config.rs
@@ -500,3 +500,18 @@ mod tests {
         assert!(p.node_override_params.is_none());
     }
 }
+
+#[cfg(test)]
+mod fixture_tests {
+    /// `IGNEUM_TEST_SETTINGS=<path> cargo test settings_fixture`: parses a real settings.json with this crate's
+    /// struct and prints what it read (6 October 2026: PC 1's copied file read as defaults; this names the field).
+    #[test]
+    fn settings_fixture_parses_when_given() {
+        let Ok(p) = std::env::var("IGNEUM_TEST_SETTINGS") else { return };
+        let t = std::fs::read_to_string(&p).unwrap();
+        match serde_json::from_str::<super::Settings>(&t) {
+            Ok(s) => println!("parsed: address {} cards {} remote_jobs {} setup_done {}", s.address, s.cards.len(), s.remote_jobs, s.setup_done),
+            Err(e) => panic!("the crate refuses the file: {e}"),
+        }
+    }
+}
diff --git a/app/igneum-app/src/ota.rs b/app/igneum-app/src/ota.rs
index b04d7fb88..7a7f12bee 100644
--- a/app/igneum-app/src/ota.rs
+++ b/app/igneum-app/src/ota.rs
@@ -184,7 +184,11 @@ impl Updater {
             if crate::platform::start_at_login_is_on() {
                 let _ = crate::platform::set_start_at_login(true);
             }
-            firewall_first_run(shared);
+            // a measurement engine (--sweep) uses the installed app's node and asks for nothing: the rule is the
+            // installed app's (the dry run of 6 October 2026 raised a second UAC prompt from here)
+            if !shared.runtime.sweep_only {
+                firewall_first_run(shared);
+            }
         }
         u.failed_versions = std::fs::read_to_string(u.failed_path()).ok().and_then(|t| serde_json::from_str::<Vec<String>>(&t).ok()).unwrap_or_default();
         // the cached manifest: the rollback floor and the consensus override are known before the first check
diff --git a/app/igneum-app/src/platform.rs b/app/igneum-app/src/platform.rs
index a3e8e6941..181b2a0de 100644
--- a/app/igneum-app/src/platform.rs
+++ b/app/igneum-app/src/platform.rs
@@ -166,17 +166,26 @@ pub fn lock_permissions(path: &Path, dir: bool) {
     }
     #[cfg(windows)]
     {
-        let _ = dir;
         let user = std::env::var("USERNAME").unwrap_or_default();
         if !user.is_empty() {
-            let _ = quiet(&mut Command::new(tool("icacls")))
-                .arg(path)
-                .args(["/inheritance:r", "/grant:r", &format!("{user}:F")])
-                .output();
+            let _ = quiet(&mut Command::new(tool("icacls"))).arg(path).args(icacls_lock_args(dir, &user)).output();
         }
     }
 }
 
+/// The icacls arguments that lock a path to the user. A folder gets an INHERITABLE grant applied to everything
+/// inside (`(OI)(CI)F`, `/T`): the old non-inheritable `user:F` cut the folder's inheritance and left any file that
+/// was COPIED in before the engine started with no entry at all (6 October 2026, PC 1: a measurement engine's
+/// settings.json, machine-id and wallet.json copied by a job read as nothing, so the engine ran on defaults with no
+/// payout address; the engine's own files, written after the lock, got the creator's default DACL and hid it).
+pub fn icacls_lock_args(dir: bool, user: &str) -> Vec<String> {
+    if dir {
+        vec!["/inheritance:r".into(), "/grant:r".into(), format!("{user}:(OI)(CI)F"), "/T".into()]
+    } else {
+        vec!["/inheritance:r".into(), "/grant:r".into(), format!("{user}:F")]
+    }
+}
+
 /// Opens a URL in the default browser (the fallback when no window host runs).
 pub fn open_url(url: &str) {
     #[cfg(target_os = "macos")]
@@ -500,6 +509,17 @@ pub fn quiet(cmd: &mut Command) -> &mut Command {
     cmd
 }
 
+#[cfg(test)]
+mod lock_tests {
+    #[test]
+    fn a_locked_folder_grants_the_user_inheritably_and_covers_what_is_inside() {
+        let d = super::icacls_lock_args(true, "Admin");
+        assert_eq!(d, vec!["/inheritance:r", "/grant:r", "Admin:(OI)(CI)F", "/T"]);
+        let f = super::icacls_lock_args(false, "Admin");
+        assert_eq!(f, vec!["/inheritance:r", "/grant:r", "Admin:F"]);
+    }
+}
+
 #[cfg(test)]
 mod tests {
     #[test]
diff --git a/relay/playbooks/ember-tune-pc1.ps1 b/relay/playbooks/ember-tune-pc1.ps1
index fd0786c99..4ed51c772 100644
--- a/relay/playbooks/ember-tune-pc1.ps1
+++ b/relay/playbooks/ember-tune-pc1.ps1
@@ -71,7 +71,7 @@ Say ("engine: " + $exe + " (" + $ver + ")")
 Write-Output ("RESULT TUNE engine " + $ver + " sha256=" + (Get-FileHash -LiteralPath $exe -Algorithm SHA256).Hash.ToLower())
 if ($ver -notmatch 'igneum-app (\d+)\.(\d+)\.(\d+)') { Write-Output 'RESULT TUNE error=version_unknown'; exit 2 }
 
-foreach ($f in @('settings.json', 'machine-id', 'wallet.json', 'tuning.json')) {
+foreach ($f in @('settings.json', 'machine-id', 'wallet.json', 'tuning.json', 'firewall-rule.json')) {   # the firewall flag too: an older kit then asks nothing
   $src = Join-Path $appDir $f
   if (Test-Path $src) { Copy-Item -LiteralPath $src -Destination (Join-Path $sApp $f) -Force }
 }