diff --git a/package.json b/package.json
index a855889..fa92a6a 100644
--- a/package.json
+++ b/package.json
@@ -181,6 +181,9 @@
     "typescript-eslint": "^8.51.0",
     "vitest": "^4.0.18"
   },
+  "overrides": {
+    "@huggingface/transformers>onnxruntime-node": "1.24.3"
+  },
   "pnpm": {
     "onlyBuiltDependencies": [
       "esbuild",
diff --git a/src/core/reranker.ts b/src/core/reranker.ts
index 9dabeac..f579289 100644
--- a/src/core/reranker.ts
+++ b/src/core/reranker.ts
@@ -11,6 +11,7 @@
 import type { SearchResult } from '../types/index.js';
 import type { PreTrainedTokenizer } from '@huggingface/transformers';
 import os from 'os';
+import { assertMinimumOnnxRuntimeNodeVersion } from '../utils/onnxruntime-version.js';
 
 const DEFAULT_RERANKER_MODEL = 'Xenova/ms-marco-MiniLM-L-6-v2';
 
@@ -48,6 +49,8 @@ async function ensureModelLoaded(): Promise<void> {
   if (initPromise) return initPromise;
 
   initPromise = (async () => {
+    assertMinimumOnnxRuntimeNodeVersion();
+
     const { AutoTokenizer, AutoModelForSequenceClassification, env } =
       await import('@huggingface/transformers');
 
diff --git a/src/embeddings/transformers.ts b/src/embeddings/transformers.ts
index bb358d1..db0b2b4 100644
--- a/src/embeddings/transformers.ts
+++ b/src/embeddings/transformers.ts
@@ -1,6 +1,7 @@
 import { EmbeddingProvider, DEFAULT_MODEL } from './types.js';
 import type { FeatureExtractionPipeline } from '@huggingface/transformers';
 import os from 'os';
+import { assertMinimumOnnxRuntimeNodeVersion } from '../utils/onnxruntime-version.js';
 import { assertOptionalDependency } from '../utils/optional-dependency.js';
 
 /**
@@ -58,6 +59,7 @@ export class TransformersEmbeddingProvider implements EmbeddingProvider {
     if (this.initPromise) return this.initPromise;
 
     assertOptionalDependency('@huggingface/transformers', '^4.2.0');
+    assertMinimumOnnxRuntimeNodeVersion();
 
     this.initPromise = this._initialize();
     return this.initPromise;
diff --git a/src/utils/onnxruntime-version.ts b/src/utils/onnxruntime-version.ts
new file mode 100644
index 0000000..2e0df77
--- /dev/null
+++ b/src/utils/onnxruntime-version.ts
@@ -0,0 +1,65 @@
+import { readFileSync } from 'node:fs';
+import { createRequire } from 'node:module';
+import path from 'node:path';
+
+/** microsoft/onnxruntime#24579 — mutex crash on macOS in 1.21.x and earlier. */
+export const MIN_ONNXRUNTIME_NODE_VERSION = '1.24.0';
+
+const resolve = createRequire(import.meta.url).resolve;
+
+export function parseSemverTriple(version: string): [number, number, number] {
+  const match = /^(\d+)\.(\d+)\.(\d+)/.exec(version.trim());
+  if (!match) {
+    return [0, 0, 0];
+  }
+  return [Number(match[1]), Number(match[2]), Number(match[3])];
+}
+
+export function isSemverAtLeast(actual: string, minimum: string): boolean {
+  const [aMajor, aMinor, aPatch] = parseSemverTriple(actual);
+  const [mMajor, mMinor, mPatch] = parseSemverTriple(minimum);
+  if (aMajor !== mMajor) {
+    return aMajor > mMajor;
+  }
+  if (aMinor !== mMinor) {
+    return aMinor > mMinor;
+  }
+  return aPatch >= mPatch;
+}
+
+function readInstalledOnnxRuntimeVersion(): string | null {
+  try {
+    const transformersPkg = resolve('@huggingface/transformers/package.json');
+    const onnxPkg = resolve('onnxruntime-node/package.json', {
+      paths: [path.dirname(transformersPkg)]
+    });
+    const pkg = JSON.parse(readFileSync(onnxPkg, 'utf8')) as { version?: string };
+    return typeof pkg.version === 'string' ? pkg.version : null;
+  } catch {
+    try {
+      const onnxPkg = resolve('onnxruntime-node/package.json');
+      const pkg = JSON.parse(readFileSync(onnxPkg, 'utf8')) as { version?: string };
+      return typeof pkg.version === 'string' ? pkg.version : null;
+    } catch {
+      return null;
+    }
+  }
+}
+
+/** Fail fast before ONNX embedding/rerank work when the native runtime is too old. */
+export function assertMinimumOnnxRuntimeNodeVersion(minimum = MIN_ONNXRUNTIME_NODE_VERSION): void {
+  const installed = readInstalledOnnxRuntimeVersion();
+  if (!installed) {
+    return;
+  }
+
+  if (isSemverAtLeast(installed, minimum)) {
+    return;
+  }
+
+  throw new Error(
+    `onnxruntime-node@${installed} can crash on macOS during embedding (mutex lock failed; see microsoft/onnxruntime#24579). ` +
+      `Install @huggingface/transformers@^4.2.0 so onnxruntime-node resolves to >=${minimum}, ` +
+      `or set EMBEDDING_PROVIDER=openai to bypass local Transformers.js.`
+  );
+}
diff --git a/tests/onnxruntime-version.test.ts b/tests/onnxruntime-version.test.ts
new file mode 100644
index 0000000..f3ae407
--- /dev/null
+++ b/tests/onnxruntime-version.test.ts
@@ -0,0 +1,47 @@
+import { readFileSync } from 'node:fs';
+import { resolve } from 'node:path';
+import { describe, expect, it } from 'vitest';
+
+import {
+  MIN_ONNXRUNTIME_NODE_VERSION,
+  assertMinimumOnnxRuntimeNodeVersion,
+  isSemverAtLeast,
+  parseSemverTriple
+} from '../src/utils/onnxruntime-version.js';
+
+const root = resolve(import.meta.dirname, '..');
+
+type PackageJson = {
+  peerDependencies?: Record<string, string>;
+  overrides?: Record<string, string>;
+  pnpm?: { overrides?: Record<string, string> };
+};
+
+describe('onnxruntime-node macOS mutex regression (#68)', () => {
+  const packageJson = JSON.parse(readFileSync(resolve(root, 'package.json'), 'utf8')) as PackageJson;
+  const lockfile = readFileSync(resolve(root, 'pnpm-lock.yaml'), 'utf8');
+
+  it('requires Transformers.js v4 peers (ships onnxruntime-node 1.24.x)', () => {
+    expect(packageJson.peerDependencies?.['@huggingface/transformers']).toBe('^4.2.0');
+  });
+
+  it('pins onnxruntime-node 1.24.3 for npm and pnpm installs', () => {
+    expect(packageJson.overrides?.['@huggingface/transformers>onnxruntime-node']).toBe('1.24.3');
+    expect(packageJson.pnpm?.overrides?.['@huggingface/transformers>onnxruntime-node']).toBe('1.24.3');
+  });
+
+  it('locks onnxruntime-node 1.24.3 in pnpm-lock.yaml', () => {
+    expect(lockfile).toContain("'@huggingface/transformers>onnxruntime-node': 1.24.3");
+    expect(lockfile).toMatch(/onnxruntime-node@1\.24\.3/);
+  });
+
+  it('compares semver triples for the minimum safe runtime', () => {
+    expect(parseSemverTriple('1.21.0')).toEqual([1, 21, 0]);
+    expect(isSemverAtLeast('1.24.3', MIN_ONNXRUNTIME_NODE_VERSION)).toBe(true);
+    expect(isSemverAtLeast('1.21.0', MIN_ONNXRUNTIME_NODE_VERSION)).toBe(false);
+  });
+
+  it('accepts onnxruntime-node 1.24.x when installed with Transformers.js', () => {
+    expect(() => assertMinimumOnnxRuntimeNodeVersion()).not.toThrow();
+  });
+});