diff --git a/src/gateway/server-methods/update.ts b/src/gateway/server-methods/update.ts
index a4eb5a93c..a72e2d0ab 100644
--- a/src/gateway/server-methods/update.ts
+++ b/src/gateway/server-methods/update.ts
@@ -90,15 +90,21 @@ export const updateHandlers: GatewayRequestHandlers = {
       sentinelPath = null;
     }
 
-    const restart = scheduleGatewaySigusr1Restart({
-      delayMs: restartDelayMs,
-      reason: "update.run",
-    });
+    // Only restart the gateway when the update actually succeeded.
+    // Restarting after a failed update leaves the process in a broken state
+    // (corrupted node_modules, partial builds) and causes a crash loop.
+    const restart =
+      result.status === "ok"
+        ? scheduleGatewaySigusr1Restart({
+            delayMs: restartDelayMs,
+            reason: "update.run",
+          })
+        : null;
 
     respond(
       true,
       {
-        ok: true,
+        ok: result.status !== "error",
         result,
         restart,
         sentinel: {
diff --git a/src/infra/update-runner.test.ts b/src/infra/update-runner.test.ts
index 912a67a14..31766593b 100644
--- a/src/infra/update-runner.test.ts
+++ b/src/infra/update-runner.test.ts
@@ -55,7 +55,7 @@ describe("runGatewayUpdate", () => {
   }) {
     const calls: string[] = [];
     let uiBuildCount = 0;
-    const doctorKey = `${process.execPath} ${path.join(tempDir, "openclaw.mjs")} doctor --non-interactive`;
+    const doctorKey = `${process.execPath} ${path.join(tempDir, "openclaw.mjs")} doctor --non-interactive --fix`;
 
     const runCommand = async (argv: string[]) => {
       const key = argv.join(" ");
@@ -173,6 +173,69 @@ describe("runGatewayUpdate", () => {
     expect(calls.some((call) => call.includes("rebase --abort"))).toBe(true);
   });
 
+  it("returns error and stops early when deps install fails", async () => {
+    await fs.mkdir(path.join(tempDir, ".git"));
+    await fs.writeFile(
+      path.join(tempDir, "package.json"),
+      JSON.stringify({ name: "openclaw", version: "1.0.0", packageManager: "pnpm@8.0.0" }),
+      "utf-8",
+    );
+    const stableTag = "v1.0.1-1";
+    const { runner, calls } = createRunner({
+      [`git -C ${tempDir} rev-parse --show-toplevel`]: { stdout: tempDir },
+      [`git -C ${tempDir} rev-parse HEAD`]: { stdout: "abc123" },
+      [`git -C ${tempDir} status --porcelain -- :!dist/control-ui/`]: { stdout: "" },
+      [`git -C ${tempDir} fetch --all --prune --tags`]: { stdout: "" },
+      [`git -C ${tempDir} tag --list v* --sort=-v:refname`]: { stdout: `${stableTag}\n` },
+      [`git -C ${tempDir} checkout --detach ${stableTag}`]: { stdout: "" },
+      "pnpm install": { code: 1, stderr: "ERR_PNPM_NETWORK" },
+    });
+
+    const result = await runGatewayUpdate({
+      cwd: tempDir,
+      runCommand: async (argv, _options) => runner(argv),
+      timeoutMs: 5000,
+      channel: "stable",
+    });
+
+    expect(result.status).toBe("error");
+    expect(result.reason).toBe("deps-install-failed");
+    expect(calls.some((call) => call === "pnpm build")).toBe(false);
+    expect(calls.some((call) => call === "pnpm ui:build")).toBe(false);
+  });
+
+  it("returns error and stops early when build fails", async () => {
+    await fs.mkdir(path.join(tempDir, ".git"));
+    await fs.writeFile(
+      path.join(tempDir, "package.json"),
+      JSON.stringify({ name: "openclaw", version: "1.0.0", packageManager: "pnpm@8.0.0" }),
+      "utf-8",
+    );
+    const stableTag = "v1.0.1-1";
+    const { runner, calls } = createRunner({
+      [`git -C ${tempDir} rev-parse --show-toplevel`]: { stdout: tempDir },
+      [`git -C ${tempDir} rev-parse HEAD`]: { stdout: "abc123" },
+      [`git -C ${tempDir} status --porcelain -- :!dist/control-ui/`]: { stdout: "" },
+      [`git -C ${tempDir} fetch --all --prune --tags`]: { stdout: "" },
+      [`git -C ${tempDir} tag --list v* --sort=-v:refname`]: { stdout: `${stableTag}\n` },
+      [`git -C ${tempDir} checkout --detach ${stableTag}`]: { stdout: "" },
+      "pnpm install": { stdout: "" },
+      "pnpm build": { code: 1, stderr: "tsc: error TS2345" },
+    });
+
+    const result = await runGatewayUpdate({
+      cwd: tempDir,
+      runCommand: async (argv, _options) => runner(argv),
+      timeoutMs: 5000,
+      channel: "stable",
+    });
+
+    expect(result.status).toBe("error");
+    expect(result.reason).toBe("build-failed");
+    expect(calls.some((call) => call === "pnpm install")).toBe(true);
+    expect(calls.some((call) => call === "pnpm ui:build")).toBe(false);
+  });
+
   it("uses stable tag when beta tag is older than release", async () => {
     await setupGitCheckout({ packageManager: "pnpm@8.0.0" });
     await setupUiIndex();
@@ -190,9 +253,10 @@ describe("runGatewayUpdate", () => {
       "pnpm install": { stdout: "" },
       "pnpm build": { stdout: "" },
       "pnpm ui:build": { stdout: "" },
-      [`${process.execPath} ${path.join(tempDir, "openclaw.mjs")} doctor --non-interactive`]: {
-        stdout: "",
-      },
+      [`${process.execPath} ${path.join(tempDir, "openclaw.mjs")} doctor --non-interactive --fix`]:
+        {
+          stdout: "",
+        },
     });
 
     const result = await runGatewayUpdate({
diff --git a/src/infra/update-runner.ts b/src/infra/update-runner.ts
index 4e84cea40..6631b6dd3 100644
--- a/src/infra/update-runner.ts
+++ b/src/infra/update-runner.ts
@@ -705,14 +705,47 @@ export async function runGatewayUpdate(opts: UpdateRunnerOptions = {}): Promise<
 
     const depsStep = await runStep(step("deps install", managerInstallArgs(manager), gitRoot));
     steps.push(depsStep);
+    if (depsStep.exitCode !== 0) {
+      return {
+        status: "error",
+        mode: "git",
+        root: gitRoot,
+        reason: "deps-install-failed",
+        before: { sha: beforeSha, version: beforeVersion },
+        steps,
+        durationMs: Date.now() - startedAt,
+      };
+    }
 
     const buildStep = await runStep(step("build", managerScriptArgs(manager, "build"), gitRoot));
     steps.push(buildStep);
+    if (buildStep.exitCode !== 0) {
+      return {
+        status: "error",
+        mode: "git",
+        root: gitRoot,
+        reason: "build-failed",
+        before: { sha: beforeSha, version: beforeVersion },
+        steps,
+        durationMs: Date.now() - startedAt,
+      };
+    }
 
     const uiBuildStep = await runStep(
       step("ui:build", managerScriptArgs(manager, "ui:build"), gitRoot),
     );
     steps.push(uiBuildStep);
+    if (uiBuildStep.exitCode !== 0) {
+      return {
+        status: "error",
+        mode: "git",
+        root: gitRoot,
+        reason: "ui-build-failed",
+        before: { sha: beforeSha, version: beforeVersion },
+        steps,
+        durationMs: Date.now() - startedAt,
+      };
+    }
 
     const doctorEntry = path.join(gitRoot, "openclaw.mjs");
     const doctorEntryExists = await fs
@@ -739,7 +772,9 @@ export async function runGatewayUpdate(opts: UpdateRunnerOptions = {}): Promise<
       };
     }
 
-    const doctorArgv = [process.execPath, doctorEntry, "doctor", "--non-interactive"];
+    // Use --fix so that doctor auto-strips unknown config keys introduced by
+    // schema changes between versions, preventing a startup validation crash.
+    const doctorArgv = [process.execPath, doctorEntry, "doctor", "--non-interactive", "--fix"];
     const doctorStep = await runStep(
       step("openclaw doctor", doctorArgv, gitRoot, { OPENCLAW_UPDATE_IN_PROGRESS: "1" }),
     );