diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6959abd2737..f7d026c773b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -38,6 +38,9 @@ Docs: https://docs.openclaw.ai
 
 ### Fixes
 
+- Plugins/startup: remove ownerless bundled runtime-dependency install locks
+  after a short grace window and include lock owner details when startup times
+  out waiting for a plugin runtime-deps lock. Thanks @steipete.
 - Agents/replies: forward sanitized underlying agent failure details on external
   channels instead of replacing unknown failures with a generic retry message.
   Thanks @steipete.
diff --git a/src/plugins/bundled-runtime-deps.test.ts b/src/plugins/bundled-runtime-deps.test.ts
index a51ccb3350c..269bc557442 100644
--- a/src/plugins/bundled-runtime-deps.test.ts
+++ b/src/plugins/bundled-runtime-deps.test.ts
@@ -766,6 +766,72 @@ describe("ensureBundledPluginRuntimeDeps", () => {
     ).toBe(false);
   });
 
+  it("does not expire fresh ownerless runtime-deps install locks", () => {
+    expect(
+      bundledRuntimeDepsTesting.shouldRemoveRuntimeDepsLock(
+        { lockDirMtimeMs: 1_000 },
+        31_000,
+        () => true,
+      ),
+    ).toBe(false);
+  });
+
+  it("does not expire ownerless runtime-deps install locks when the owner file changed recently", () => {
+    expect(
+      bundledRuntimeDepsTesting.shouldRemoveRuntimeDepsLock(
+        { lockDirMtimeMs: 1_000, ownerFileMtimeMs: 31_000 },
+        61_000,
+        () => true,
+      ),
+    ).toBe(false);
+  });
+
+  it("expires ownerless runtime-deps install locks after the owner write grace window", () => {
+    expect(
+      bundledRuntimeDepsTesting.shouldRemoveRuntimeDepsLock(
+        { lockDirMtimeMs: 1_000 },
+        31_001,
+        () => true,
+      ),
+    ).toBe(true);
+  });
+
+  it("expires ownerless runtime-deps install locks when lock and owner file are stale", () => {
+    expect(
+      bundledRuntimeDepsTesting.shouldRemoveRuntimeDepsLock(
+        { lockDirMtimeMs: 1_000, ownerFileMtimeMs: 2_000 },
+        32_001,
+        () => true,
+      ),
+    ).toBe(true);
+  });
+
+  it("includes runtime-deps lock owner details in timeout messages", () => {
+    const message = bundledRuntimeDepsTesting.formatRuntimeDepsLockTimeoutMessage({
+      lockDir: "/tmp/openclaw-plugin/.openclaw-runtime-deps.lock",
+      owner: {
+        pid: 0,
+        createdAtMs: 1_000,
+        ownerFileState: "invalid",
+        ownerFilePath: "/tmp/openclaw-plugin/.openclaw-runtime-deps.lock/owner.json",
+        ownerFileMtimeMs: 2_500,
+        ownerFileIsSymlink: true,
+        lockDirMtimeMs: 2_000,
+      },
+      waitedMs: 300_123,
+      nowMs: 303_000,
+    });
+
+    expect(message).toContain("waited=300123ms");
+    expect(message).toContain("ownerFile=invalid");
+    expect(message).toContain("ownerFileSymlink=true");
+    expect(message).toContain("pid=0 alive=false");
+    expect(message).toContain("ownerAge=302000ms");
+    expect(message).toContain("ownerFileAge=300500ms");
+    expect(message).toContain("lockAge=301000ms");
+    expect(message).toContain(".openclaw-runtime-deps.lock/owner.json");
+  });
+
   it("removes stale runtime-deps install locks before repairing deps", () => {
     const packageRoot = makeTempDir();
     const pluginRoot = path.join(packageRoot, "dist", "extensions", "openai");
@@ -808,6 +874,100 @@ describe("ensureBundledPluginRuntimeDeps", () => {
     expect(fs.existsSync(lockDir)).toBe(false);
   });
 
+  it("removes stale malformed runtime-deps install locks before repairing deps", () => {
+    const packageRoot = makeTempDir();
+    const pluginRoot = path.join(packageRoot, "dist", "extensions", "browser");
+    fs.mkdirSync(pluginRoot, { recursive: true });
+    fs.writeFileSync(
+      path.join(pluginRoot, "package.json"),
+      JSON.stringify({
+        dependencies: {
+          "browser-runtime": "1.0.0",
+        },
+      }),
+    );
+    const installRoot = resolveBundledRuntimeDependencyInstallRoot(pluginRoot, { env: {} });
+    const lockDir = path.join(installRoot, ".openclaw-runtime-deps.lock");
+    fs.mkdirSync(lockDir, { recursive: true });
+    const ownerPath = path.join(lockDir, "owner.json");
+    fs.writeFileSync(ownerPath, "{", "utf8");
+    fs.utimesSync(ownerPath, new Date(0), new Date(0));
+    fs.utimesSync(lockDir, new Date(0), new Date(0));
+
+    const calls: BundledRuntimeDepsInstallParams[] = [];
+    const result = ensureBundledPluginRuntimeDeps({
+      env: {},
+      installDeps: (params) => {
+        calls.push(params);
+        fs.mkdirSync(path.join(params.installRoot, "node_modules", "browser-runtime"), {
+          recursive: true,
+        });
+        fs.writeFileSync(
+          path.join(params.installRoot, "node_modules", "browser-runtime", "package.json"),
+          JSON.stringify({ name: "browser-runtime", version: "1.0.0" }),
+        );
+      },
+      pluginId: "browser",
+      pluginRoot,
+    });
+
+    expect(result).toEqual({
+      installedSpecs: ["browser-runtime@1.0.0"],
+      retainSpecs: ["browser-runtime@1.0.0"],
+    });
+    expect(calls).toHaveLength(1);
+    expect(fs.existsSync(lockDir)).toBe(false);
+  });
+
+  const itSupportsSymlinks = process.platform === "win32" ? it.skip : it;
+  itSupportsSymlinks(
+    "removes stale runtime-deps install locks with broken owner symlinks before repairing deps",
+    () => {
+      const packageRoot = makeTempDir();
+      const pluginRoot = path.join(packageRoot, "dist-runtime", "extensions", "browser");
+      fs.mkdirSync(pluginRoot, { recursive: true });
+      fs.writeFileSync(
+        path.join(pluginRoot, "package.json"),
+        JSON.stringify({
+          dependencies: {
+            "browser-runtime": "1.0.0",
+          },
+        }),
+      );
+      const installRoot = resolveBundledRuntimeDependencyInstallRoot(pluginRoot, { env: {} });
+      const lockDir = path.join(installRoot, ".openclaw-runtime-deps.lock");
+      fs.mkdirSync(lockDir, { recursive: true });
+      const ownerPath = path.join(lockDir, "owner.json");
+      fs.symlinkSync("../missing-owner.json", ownerPath);
+      fs.lutimesSync(ownerPath, new Date(0), new Date(0));
+      fs.utimesSync(lockDir, new Date(0), new Date(0));
+
+      const calls: BundledRuntimeDepsInstallParams[] = [];
+      const result = ensureBundledPluginRuntimeDeps({
+        env: {},
+        installDeps: (params) => {
+          calls.push(params);
+          fs.mkdirSync(path.join(params.installRoot, "node_modules", "browser-runtime"), {
+            recursive: true,
+          });
+          fs.writeFileSync(
+            path.join(params.installRoot, "node_modules", "browser-runtime", "package.json"),
+            JSON.stringify({ name: "browser-runtime", version: "1.0.0" }),
+          );
+        },
+        pluginId: "browser",
+        pluginRoot,
+      });
+
+      expect(result).toEqual({
+        installedSpecs: ["browser-runtime@1.0.0"],
+        retainSpecs: ["browser-runtime@1.0.0"],
+      });
+      expect(calls).toHaveLength(1);
+      expect(fs.existsSync(lockDir)).toBe(false);
+    },
+  );
+
   it("does not install when runtime deps are only workspace links", () => {
     const packageRoot = makeTempDir();
     const extensionsRoot = path.join(packageRoot, "dist", "extensions");
diff --git a/src/plugins/bundled-runtime-deps.ts b/src/plugins/bundled-runtime-deps.ts
index facef964ab9..32e59f67306 100644
--- a/src/plugins/bundled-runtime-deps.ts
+++ b/src/plugins/bundled-runtime-deps.ts
@@ -54,6 +54,7 @@ const BUNDLED_RUNTIME_DEPS_LOCK_OWNER_FILE = "owner.json";
 const BUNDLED_RUNTIME_DEPS_LOCK_WAIT_MS = 100;
 const BUNDLED_RUNTIME_DEPS_LOCK_TIMEOUT_MS = 5 * 60_000;
 const BUNDLED_RUNTIME_DEPS_LOCK_STALE_MS = 10 * 60_000;
+const BUNDLED_RUNTIME_DEPS_OWNERLESS_LOCK_STALE_MS = 30_000;
 
 export type BundledRuntimeDepsNpmRunner = {
   command: string;
@@ -186,21 +187,80 @@ function isProcessAlive(pid: number): boolean {
   try {
     process.kill(pid, 0);
     return true;
-  } catch {
-    return false;
+  } catch (error) {
+    return (error as NodeJS.ErrnoException).code === "EPERM";
   }
 }
 
-function readRuntimeDepsLockOwner(lockDir: string): { pid?: number; createdAtMs?: number } {
-  const owner = readJsonObject(path.join(lockDir, BUNDLED_RUNTIME_DEPS_LOCK_OWNER_FILE));
+type RuntimeDepsLockOwner = {
+  pid?: number;
+  createdAtMs?: number;
+  ownerFileState: "ok" | "missing" | "invalid";
+  ownerFilePath: string;
+  ownerFileMtimeMs?: number;
+  ownerFileIsSymlink?: boolean;
+  lockDirMtimeMs?: number;
+};
+
+function readRuntimeDepsLockOwner(lockDir: string): RuntimeDepsLockOwner {
+  const ownerFilePath = path.join(lockDir, BUNDLED_RUNTIME_DEPS_LOCK_OWNER_FILE);
+  let owner: JsonObject | null = null;
+  let ownerFileState: RuntimeDepsLockOwner["ownerFileState"] = "missing";
+  let ownerFileMtimeMs: number | undefined;
+  let ownerFileIsSymlink: boolean | undefined;
+  try {
+    const ownerFileStat = fs.lstatSync(ownerFilePath);
+    ownerFileMtimeMs = ownerFileStat.mtimeMs;
+    ownerFileIsSymlink = ownerFileStat.isSymbolicLink();
+  } catch {
+    // The owner file may not exist yet, or may have been removed by the lock owner.
+  }
+  try {
+    const parsed = JSON.parse(fs.readFileSync(ownerFilePath, "utf8")) as unknown;
+    if (parsed && typeof parsed === "object" && !Array.isArray(parsed)) {
+      owner = parsed as JsonObject;
+      ownerFileState = "ok";
+    } else {
+      ownerFileState = "invalid";
+    }
+  } catch (error) {
+    ownerFileState =
+      (error as NodeJS.ErrnoException).code === "ENOENT" && ownerFileMtimeMs === undefined
+        ? "missing"
+        : "invalid";
+  }
+  let lockDirMtimeMs: number | undefined;
+  try {
+    lockDirMtimeMs = fs.statSync(lockDir).mtimeMs;
+  } catch {
+    // The lock may have disappeared between the mkdir failure and diagnostics.
+  }
   return {
     pid: typeof owner?.pid === "number" ? owner.pid : undefined,
     createdAtMs: typeof owner?.createdAtMs === "number" ? owner.createdAtMs : undefined,
+    ownerFileState,
+    ownerFilePath,
+    ownerFileMtimeMs,
+    ownerFileIsSymlink,
+    lockDirMtimeMs,
   };
 }
 
+function latestFiniteMs(values: readonly (number | undefined)[]): number | undefined {
+  let latest: number | undefined;
+  for (const value of values) {
+    if (typeof value !== "number" || !Number.isFinite(value)) {
+      continue;
+    }
+    if (latest === undefined || value > latest) {
+      latest = value;
+    }
+  }
+  return latest;
+}
+
 function shouldRemoveRuntimeDepsLock(
-  owner: { pid?: number; createdAtMs?: number },
+  owner: Pick<RuntimeDepsLockOwner, "pid" | "createdAtMs" | "lockDirMtimeMs" | "ownerFileMtimeMs">,
   nowMs: number,
   isAlive: (pid: number) => boolean = isProcessAlive,
 ): boolean {
@@ -208,13 +268,55 @@ function shouldRemoveRuntimeDepsLock(
     return !isAlive(owner.pid);
   }
 
+  if (typeof owner.createdAtMs === "number") {
+    return nowMs - owner.createdAtMs > BUNDLED_RUNTIME_DEPS_LOCK_STALE_MS;
+  }
+
+  const ownerlessObservedAtMs = latestFiniteMs([owner.lockDirMtimeMs, owner.ownerFileMtimeMs]);
   return (
-    typeof owner.createdAtMs === "number" &&
-    nowMs - owner.createdAtMs > BUNDLED_RUNTIME_DEPS_LOCK_STALE_MS
+    typeof ownerlessObservedAtMs === "number" &&
+    nowMs - ownerlessObservedAtMs > BUNDLED_RUNTIME_DEPS_OWNERLESS_LOCK_STALE_MS
+  );
+}
+
+function formatDurationMs(ms: number | undefined): string {
+  return typeof ms === "number" && Number.isFinite(ms) ? `${Math.max(0, Math.round(ms))}ms` : "n/a";
+}
+
+function formatRuntimeDepsLockTimeoutMessage(params: {
+  lockDir: string;
+  owner: RuntimeDepsLockOwner;
+  waitedMs: number;
+  nowMs: number;
+}): string {
+  const ownerAgeMs =
+    typeof params.owner.createdAtMs === "number"
+      ? params.nowMs - params.owner.createdAtMs
+      : undefined;
+  const lockAgeMs =
+    typeof params.owner.lockDirMtimeMs === "number"
+      ? params.nowMs - params.owner.lockDirMtimeMs
+      : undefined;
+  const ownerFileAgeMs =
+    typeof params.owner.ownerFileMtimeMs === "number"
+      ? params.nowMs - params.owner.ownerFileMtimeMs
+      : undefined;
+  const pidDetail =
+    typeof params.owner.pid === "number"
+      ? `pid=${params.owner.pid} alive=${isProcessAlive(params.owner.pid)}`
+      : "pid=missing";
+  const ownerFileSymlink =
+    typeof params.owner.ownerFileIsSymlink === "boolean" ? params.owner.ownerFileIsSymlink : "n/a";
+  return (
+    `Timed out waiting for bundled runtime deps lock at ${params.lockDir} ` +
+    `(waited=${formatDurationMs(params.waitedMs)}, ownerFile=${params.owner.ownerFileState}, ownerFileSymlink=${ownerFileSymlink}, ` +
+    `${pidDetail}, ownerAge=${formatDurationMs(ownerAgeMs)}, ownerFileAge=${formatDurationMs(ownerFileAgeMs)}, lockAge=${formatDurationMs(lockAgeMs)}, ` +
+    `ownerFilePath=${params.owner.ownerFilePath}). If no OpenClaw/npm install is running, remove the lock directory and retry.`
   );
 }
 
 export const __testing = {
+  formatRuntimeDepsLockTimeoutMessage,
   shouldRemoveRuntimeDepsLock,
 };
 
@@ -240,11 +342,16 @@ function withBundledRuntimeDepsInstallRootLock<T>(installRoot: string, run: () =
   while (!locked) {
     try {
       fs.mkdirSync(lockDir);
-      fs.writeFileSync(
-        path.join(lockDir, BUNDLED_RUNTIME_DEPS_LOCK_OWNER_FILE),
-        `${JSON.stringify({ pid: process.pid, createdAtMs: Date.now() }, null, 2)}\n`,
-        "utf8",
-      );
+      try {
+        fs.writeFileSync(
+          path.join(lockDir, BUNDLED_RUNTIME_DEPS_LOCK_OWNER_FILE),
+          `${JSON.stringify({ pid: process.pid, createdAtMs: Date.now() }, null, 2)}\n`,
+          "utf8",
+        );
+      } catch (ownerWriteError) {
+        fs.rmSync(lockDir, { recursive: true, force: true });
+        throw ownerWriteError;
+      }
       locked = true;
     } catch (error) {
       const code = (error as NodeJS.ErrnoException).code;
@@ -252,10 +359,19 @@ function withBundledRuntimeDepsInstallRootLock<T>(installRoot: string, run: () =
         throw error;
       }
       removeRuntimeDepsLockIfStale(lockDir, Date.now());
-      if (Date.now() - startedAt > BUNDLED_RUNTIME_DEPS_LOCK_TIMEOUT_MS) {
-        throw new Error(`Timed out waiting for bundled runtime deps lock at ${lockDir}`, {
-          cause: error,
-        });
+      const nowMs = Date.now();
+      if (nowMs - startedAt > BUNDLED_RUNTIME_DEPS_LOCK_TIMEOUT_MS) {
+        throw new Error(
+          formatRuntimeDepsLockTimeoutMessage({
+            lockDir,
+            owner: readRuntimeDepsLockOwner(lockDir),
+            waitedMs: nowMs - startedAt,
+            nowMs,
+          }),
+          {
+            cause: error,
+          },
+        );
       }
       sleepSync(BUNDLED_RUNTIME_DEPS_LOCK_WAIT_MS);
     }