diff --git a/tests/config/owner-registry-isolation.test.ts b/tests/config/owner-registry-isolation.test.ts
index 19cef25d2d..c13c16ade3 100644
--- a/tests/config/owner-registry-isolation.test.ts
+++ b/tests/config/owner-registry-isolation.test.ts
@@ -34,7 +34,9 @@ describe("owner registry home isolation", () => {
           import { ownerRegistryDir, readOwnerRegistry, registerOwnerRegistryHome,
             unregisterOwnerRegistryHome } from ${JSON.stringify(registryModule)};
           const startupHome = homedir();
-          process.env.HOME = process.env.USERPROFILE = ${JSON.stringify(home.path("worker"))};
+          // Windows homedir() follows USERPROFILE changes. Keep production's default
+          // home stable; only guarded callers exercise a rewritten worker home.
+          if (${guarded}) process.env.HOME = process.env.USERPROFILE = ${JSON.stringify(home.path("worker"))};
           // No preload and no registry override: child callers must still be isolated.
           delete process.env.OCX_OWNER_REGISTRY_DIR;
           const dir = ownerRegistryDir();
@@ -54,6 +56,8 @@ describe("owner registry home isolation", () => {
               unregisterOwnerRegistryHome(${JSON.stringify(foreignHome)});
             }
             delete process.env.OCX_OWNER_REGISTRY_DIR;
+            // Unpin into the protected home on cached and dynamic homedir() runtimes.
+            process.env.HOME = process.env.USERPROFILE = startupHome;
             delete process.env.OPENCODEX_HOME;
             try { readOwnerRegistry(); } catch { unpinnedRefused = true; }
           }
diff --git a/tests/service/service-state-isolation.test.ts b/tests/service/service-state-isolation.test.ts
index 5464adc3f4..68c449584c 100644
--- a/tests/service/service-state-isolation.test.ts
+++ b/tests/service/service-state-isolation.test.ts
@@ -30,9 +30,10 @@ describe("service state home isolation", () => {
           import { homedir } from "node:os";
           import { readServiceInstallState, serviceStatePathsForOpenCodexHome,
             writeServiceInstallState } from ${JSON.stringify(stateModule)};
-          // Match the preload: changing HOME cannot move Bun's cached startup home.
           const startupHome = homedir();
-          process.env.HOME = process.env.USERPROFILE = ${JSON.stringify(home.path("worker"))};
+          // Windows homedir() follows USERPROFILE changes. Keep production's default
+          // home stable; only guarded callers exercise a rewritten worker home.
+          if (${guarded}) process.env.HOME = process.env.USERPROFILE = ${JSON.stringify(home.path("worker"))};
           const before = readServiceInstallState();
           const pinned = serviceStatePathsForOpenCodexHome(${JSON.stringify(nextConfigHome)});
           writeServiceInstallState("scheduler", null);