diff --git a/codex-rs/windows-sandbox-rs/src/helper_materialization.rs b/codex-rs/windows-sandbox-rs/src/helper_materialization.rs
index bcb1847ccb..e6519ac7f2 100644
--- a/codex-rs/windows-sandbox-rs/src/helper_materialization.rs
+++ b/codex-rs/windows-sandbox-rs/src/helper_materialization.rs
@@ -409,38 +409,11 @@ mod tests {
     use super::helper_version_suffix;
     use super::materialized_file_name;
     use pretty_assertions::assert_eq;
-    use std::ffi::OsString;
     use std::fs;
     use std::path::Path;
     use std::path::PathBuf;
     use tempfile::TempDir;
 
-    struct EnvVarGuard {
-        key: &'static str,
-        original: Option<OsString>,
-    }
-
-    impl EnvVarGuard {
-        fn set(key: &'static str, value: &std::ffi::OsStr) -> Self {
-            let original = std::env::var_os(key);
-            unsafe {
-                std::env::set_var(key, value);
-            }
-            Self { key, original }
-        }
-    }
-
-    impl Drop for EnvVarGuard {
-        fn drop(&mut self) {
-            unsafe {
-                match &self.original {
-                    Some(value) => std::env::set_var(self.key, value),
-                    None => std::env::remove_var(self.key),
-                }
-            }
-        }
-    }
-
     #[test]
     fn copy_from_source_if_needed_copies_missing_destination() {
         let tmp = TempDir::new().expect("tempdir");
@@ -634,7 +607,6 @@ mod tests {
         fs::write(&canonical_exe, b"codex").expect("write canonical exe");
         fs::write(&helper, b"runner").expect("write helper");
         symlink_file(&canonical_exe, &launcher_exe);
-        let _codex_home_guard = EnvVarGuard::set("CODEX_HOME", codex_home.as_os_str());
 
         let resolved = bundled_executable_path_for_exe(&launcher_exe, "codex-command-runner.exe")
             .expect("helper path");
diff --git a/codex-rs/windows-sandbox-rs/src/setup.rs b/codex-rs/windows-sandbox-rs/src/setup.rs
index fd895031bb..ecd368a652 100644
--- a/codex-rs/windows-sandbox-rs/src/setup.rs
+++ b/codex-rs/windows-sandbox-rs/src/setup.rs
@@ -1367,6 +1367,40 @@ mod tests {
         assert_eq!(resolved, setup_exe);
     }
 
+    #[test]
+    fn setup_exe_lookup_follows_canonicalized_launcher_path() {
+        let tmp = TempDir::new().expect("tempdir");
+        let codex_home = tmp.path().join("codex-home");
+        let release_dir = codex_home
+            .join("packages")
+            .join("standalone")
+            .join("releases")
+            .join("0.142.5-x86_64-pc-windows-msvc");
+        let bin_dir = release_dir.join(BIN_DIRNAME);
+        let resources_dir = release_dir.join(RESOURCES_DIRNAME);
+        let launcher_dir = tmp
+            .path()
+            .join("AppData")
+            .join("Local")
+            .join("Programs")
+            .join("OpenAI")
+            .join("Codex")
+            .join(BIN_DIRNAME);
+        fs::create_dir_all(&bin_dir).expect("create package bin dir");
+        fs::create_dir_all(&resources_dir).expect("create resources dir");
+        fs::create_dir_all(&launcher_dir).expect("create launcher dir");
+        let canonical_exe = bin_dir.join("codex.exe");
+        let launcher_exe = launcher_dir.join("codex.exe");
+        let setup_exe = resources_dir.join("codex-windows-sandbox-setup.exe");
+        fs::write(&canonical_exe, b"codex").expect("write canonical exe");
+        fs::write(&setup_exe, b"setup").expect("write setup exe");
+        symlink_file(&canonical_exe, &launcher_exe);
+
+        let resolved = find_setup_exe_for_current_exe(&launcher_exe).expect("setup exe");
+
+        assert_eq!(resolved, setup_exe);
+    }
+
     #[test]
     fn loopback_proxy_url_parsing_rejects_non_loopback_and_zero_port() {
         assert_eq!(
@@ -1397,6 +1431,16 @@ mod tests {
         assert_eq!(proxy_ports_from_env(&env), vec![1081, 8080]);
     }
 
+    #[cfg(unix)]
+    fn symlink_file(original: &Path, link: &Path) {
+        std::os::unix::fs::symlink(original, link).expect("create symlink");
+    }
+
+    #[cfg(windows)]
+    fn symlink_file(original: &Path, link: &Path) {
+        std::os::windows::fs::symlink_file(original, link).expect("create symlink");
+    }
+
     #[test]
     fn offline_proxy_settings_ignore_proxy_env_when_online_identity_selected() {
         let mut env = HashMap::new();