diff --git a/docs/cli/doctor.md b/docs/cli/doctor.md
index 607166bc626e..5d26dc91aa5b 100644
--- a/docs/cli/doctor.md
+++ b/docs/cli/doctor.md
@@ -373,6 +373,7 @@ compare restored legacy artifacts with the SQLite rows before importing.
 - `--lint` is stricter than `--non-interactive`: always read-only, never prompts, never applies safe migrations. Use `doctor --fix` or `doctor --repair` when you want doctor to make changes.
 - Doctor does not execute `exec` SecretRefs while checking secrets by default. Use `--allow-exec` (with or without `--lint`) only when you intentionally want doctor to run those configured secret resolvers.
 - Any config write (including a `--fix` repair) rotates a backup to `~/.openclaw/openclaw.json.bak` (with a numbered `.bak.1`..`.bak.4` ring). `--fix` also drops unknown config keys reported by schema validation, listing each removal; it skips this while an update is in progress so partially written upgrade state is not stripped before its migration finishes.
+- If `openclaw.json` cannot be parsed and no last-known-good config can be recovered, `doctor --fix` preserves the original as `openclaw.json.clobbered.<timestamp>`, leaves the current file unchanged, and exits with an error instead of writing a partial replacement.
 - Set `OPENCLAW_SERVICE_REPAIR_POLICY=external` when another supervisor owns the gateway lifecycle. Doctor still reports gateway/service health and applies non-service repairs, but skips service install/start/restart/bootstrap and legacy service cleanup.
 - On Linux, doctor ignores inactive extra gateway-like systemd units and does not rewrite command/entrypoint metadata for a running systemd gateway service during repair. Stop the service first, or use `openclaw gateway install --force` to replace the active launcher.
 - `doctor --fix --non-interactive` reports missing or stale gateway service definitions but does not install or rewrite them outside update repair mode. Run `openclaw gateway install` for a missing service, or `openclaw gateway install --force` to replace the launcher.
diff --git a/src/commands/doctor-config-preflight.test.ts b/src/commands/doctor-config-preflight.test.ts
index bb0cb49a6f91..c4810bd6efea 100644
--- a/src/commands/doctor-config-preflight.test.ts
+++ b/src/commands/doctor-config-preflight.test.ts
@@ -1,5 +1,6 @@
 // Doctor config preflight tests cover last-known-good snapshots and config snapshot promotion.
 import fs from "node:fs/promises";
+import path from "node:path";
 import { afterEach, describe, expect, it } from "vitest";
 import { promoteConfigSnapshotToLastKnownGood, readConfigFileSnapshot } from "../config/config.js";
 import { withTempHome, writeOpenClawConfig } from "../config/test-helpers.js";
@@ -122,6 +123,36 @@ describe("runDoctorConfigPreflight", () => {
     });
   });
 
+  it("preserves and rejects unparseable config without last-known-good during repair preflight", async () => {
+    await withTempHome(async (home) => {
+      const configPath = path.join(home, ".openclaw", "openclaw.json");
+      const brokenRaw = '{ "gateway": { "mode": "local" }, "models": {';
+      await fs.mkdir(path.dirname(configPath), { recursive: true });
+      await fs.writeFile(configPath, brokenRaw, "utf-8");
+
+      const failure = await runDoctorConfigPreflight({
+        migrateState: false,
+        migrateLegacyConfig: false,
+        repairPrefixedConfig: true,
+        invalidConfigNote: false,
+      }).then(
+        () => null,
+        (error: unknown) => error,
+      );
+
+      expect(failure).toBeInstanceOf(Error);
+      expect((failure as Error).message).toContain("Config could not be parsed or recovered.");
+
+      await expect(fs.readFile(configPath, "utf-8")).resolves.toBe(brokenRaw);
+      const entries = await fs.readdir(path.dirname(configPath));
+      const clobbered = entries.filter((entry) => entry.startsWith("openclaw.json.clobbered."));
+      expect(clobbered).toHaveLength(1);
+      const clobberedPath = path.join(path.dirname(configPath), clobbered[0] ?? "missing");
+      expect((failure as Error).message).toContain(`Original preserved at ${clobberedPath}.`);
+      await expect(fs.readFile(clobberedPath, "utf-8")).resolves.toBe(brokenRaw);
+    });
+  });
+
   it("does not restore last-known-good for stale plugins.deny entries", async () => {
     await withTempHome(async (home) => {
       const configPath = await writeOpenClawConfig(home, {
diff --git a/src/commands/doctor-config-preflight.ts b/src/commands/doctor-config-preflight.ts
index a693f08690d3..4ef1ba83256e 100644
--- a/src/commands/doctor-config-preflight.ts
+++ b/src/commands/doctor-config-preflight.ts
@@ -4,6 +4,8 @@ import path from "node:path";
 import { note } from "../../packages/terminal-core/src/note.js";
 import { cloneEnvWithPlatformSemantics } from "../config/env-vars.js";
 import {
+  parseConfigJson5,
+  preserveConfigSnapshotAsClobbered,
   readConfigFileSnapshot,
   recoverConfigFromJsonRootSuffix,
   recoverConfigFromLastKnownGood,
@@ -341,6 +343,21 @@ export async function runDoctorConfigPreflight(
         );
         snapshot = addDoctorLegacyIssues(await readConfigFileSnapshot(readOptions));
       }
+      if (
+        !snapshot.valid &&
+        typeof snapshot.raw === "string" &&
+        !parseConfigJson5(snapshot.raw).ok
+      ) {
+        const clobberedPath = await preserveConfigSnapshotAsClobbered(snapshot);
+        if (!clobberedPath) {
+          throw new Error(
+            `Config could not be parsed or recovered, and doctor could not preserve a .clobbered snapshot. The original remains unchanged at ${snapshot.path}; refusing to apply repairs.`,
+          );
+        }
+        throw new Error(
+          `Config could not be parsed or recovered. Original preserved at ${clobberedPath}. The current file remains unchanged; refusing to apply repairs.`,
+        );
+      }
     }
     const invalidConfigNote =
       options.invalidConfigNote ?? "Config invalid; doctor will run with best-effort config.";
diff --git a/src/config/io.factory.ts b/src/config/io.factory.ts
index d33a745b0112..60fb574c9e15 100644
--- a/src/config/io.factory.ts
+++ b/src/config/io.factory.ts
@@ -1,6 +1,7 @@
 import { createConfigIoContext } from "./io.context.js";
 import { loadConfigFromContext } from "./io.load.js";
 import {
+  preserveConfigSnapshotAsClobbered,
   promoteConfigSnapshotToLastKnownGood,
   recoverConfigFromLastKnownGood,
 } from "./io.observe-recovery.js";
@@ -46,6 +47,8 @@ export function createConfigIO(options: ConfigIoFactoryOptions = {}) {
         snapshot: params.snapshot,
         reason: params.reason,
       }),
+    preserveConfigSnapshotAsClobbered: (snapshot: ConfigFileSnapshot) =>
+      preserveConfigSnapshotAsClobbered({ deps: context.deps, snapshot }),
     recoverConfigFromJsonRootSuffix: (snapshot: ConfigFileSnapshot) =>
       recoverConfigFromJsonRootSuffixWithContext(context, snapshot),
     writeConfigFile: (
diff --git a/src/config/io.observe-recovery.ts b/src/config/io.observe-recovery.ts
index 84e24f117b4a..fae343b3b2a5 100644
--- a/src/config/io.observe-recovery.ts
+++ b/src/config/io.observe-recovery.ts
@@ -943,10 +943,9 @@ export async function recoverConfigFromLastKnownGood(params: {
     stat: stat as ConfigStatMetadataSource,
     observedAt: now,
   });
-  const clobberedPath = await persistBoundedClobberedConfigSnapshot({
+  const clobberedPath = await preserveConfigSnapshotAsClobbered({
     deps,
-    configPath: snapshot.path,
-    raw: snapshot.raw,
+    snapshot,
     observedAt: now,
   });
   await deps.fs.promises.writeFile(snapshot.path, backupRaw, {
@@ -987,4 +986,20 @@ export async function recoverConfigFromLastKnownGood(params: {
   );
   return true;
 }
+
+export async function preserveConfigSnapshotAsClobbered(params: {
+  deps: ObserveRecoveryDeps;
+  snapshot: ConfigFileSnapshot;
+  observedAt?: string;
+}): Promise<string | null> {
+  if (!params.snapshot.exists || typeof params.snapshot.raw !== "string") {
+    return null;
+  }
+  return await persistBoundedClobberedConfigSnapshot({
+    deps: params.deps,
+    configPath: params.snapshot.path,
+    raw: params.snapshot.raw,
+    observedAt: params.observedAt ?? new Date().toISOString(),
+  });
+}
 /* oxlint-disable max-lines -- TODO: split this grandfathered oversized file. */
diff --git a/src/config/io.runtime.ts b/src/config/io.runtime.ts
index cd9f1a3f0fbe..a962a3e60d29 100644
--- a/src/config/io.runtime.ts
+++ b/src/config/io.runtime.ts
@@ -186,6 +186,12 @@ export async function recoverConfigFromLastKnownGood(params: {
   return await createConfigIO().recoverConfigFromLastKnownGood(params);
 }
 
+export async function preserveConfigSnapshotAsClobbered(
+  snapshot: ConfigFileSnapshot,
+): Promise<string | null> {
+  return await createConfigIO().preserveConfigSnapshotAsClobbered(snapshot);
+}
+
 export async function recoverConfigFromJsonRootSuffix(
   snapshot: ConfigFileSnapshot,
 ): Promise<boolean> {
diff --git a/src/config/io.ts b/src/config/io.ts
index c25d169a1ca3..1ca78a17a899 100644
--- a/src/config/io.ts
+++ b/src/config/io.ts
@@ -9,6 +9,7 @@ export {
   clearConfigCache,
   getRuntimeConfig,
   loadConfig,
+  preserveConfigSnapshotAsClobbered,
   promoteConfigSnapshotToLastKnownGood,
   readBestEffortConfig,
   readBestEffortConfigSnapshot,