diff --git a/apps/desktop/resources/entitlements.mas.autofill-enabled.plist b/apps/desktop/resources/entitlements.mas.autofill-enabled.plist
index 9b6f39457295..2a8da2f273fd 100644
--- a/apps/desktop/resources/entitlements.mas.autofill-enabled.plist
+++ b/apps/desktop/resources/entitlements.mas.autofill-enabled.plist
@@ -24,6 +24,7 @@
 	<true/>
 	<key>com.apple.security.temporary-exception.files.home-relative-path.read-write</key>
 	<array>
+		<string>/Library/Application Support/Mozilla</string>
 		<string>/Library/Application Support/Mozilla/NativeMessagingHosts/</string>
 		<string>/Library/Application Support/Google/Chrome/NativeMessagingHosts/</string>
 		<string>/Library/Application Support/Google/Chrome Beta/NativeMessagingHosts/</string>
diff --git a/apps/desktop/resources/entitlements.mas.plist b/apps/desktop/resources/entitlements.mas.plist
index 152c075bdced..7f554f143869 100644
--- a/apps/desktop/resources/entitlements.mas.plist
+++ b/apps/desktop/resources/entitlements.mas.plist
@@ -24,6 +24,7 @@
 	<true/>
 	<key>com.apple.security.temporary-exception.files.home-relative-path.read-write</key>
 	<array>
+		<string>/Library/Application Support/Mozilla</string>
 		<string>/Library/Application Support/Mozilla/NativeMessagingHosts/</string>
 		<string>/Library/Application Support/Google/Chrome/NativeMessagingHosts/</string>
 		<string>/Library/Application Support/Google/Chrome Beta/NativeMessagingHosts/</string>
diff --git a/apps/desktop/src/main/native-messaging.main.spec.ts b/apps/desktop/src/main/native-messaging.main.spec.ts
new file mode 100644
index 000000000000..7794dbae0bc6
--- /dev/null
+++ b/apps/desktop/src/main/native-messaging.main.spec.ts
@@ -0,0 +1,176 @@
+import { existsSync, promises as fs } from "fs";
+
+import { mock, MockProxy } from "jest-mock-extended";
+
+import { LogService } from "@bitwarden/common/platform/abstractions/log.service";
+
+import { NativeMessagingMain } from "./native-messaging.main";
+import { WindowMain } from "./window.main";
+
+jest.mock("electron", () => ({
+  ipcMain: { handle: jest.fn(), on: jest.fn() },
+}));
+
+jest.mock("@bitwarden/desktop-napi", () => ({
+  ipc: { NativeIpcServer: { listen: jest.fn() } },
+  windows_registry: { createKey: jest.fn(), deleteKey: jest.fn() },
+}));
+
+jest.mock("fs", () => ({
+  ...jest.requireActual("fs"),
+  existsSync: jest.fn(),
+  promises: {
+    ...jest.requireActual("fs").promises,
+    mkdir: jest.fn(),
+    writeFile: jest.fn(),
+    unlink: jest.fn(),
+  },
+}));
+
+jest.mock("os", () => ({
+  ...jest.requireActual("os"),
+  homedir: jest.fn(() => "/Users/test"),
+  userInfo: jest.fn(() => ({ homedir: "/Users/test", username: "test" })),
+}));
+
+jest.mock("../utils", () => ({ isDev: () => false }));
+
+describe("NativeMessagingMain", () => {
+  const APP_SUPPORT = "/Users/test/Library/Application Support";
+  const EXE_PATH = "/Applications/Bitwarden.app/Contents/MacOS/Bitwarden";
+  const BINARY_PATH = "/Applications/Bitwarden.app/Contents/MacOS/desktop_proxy";
+
+  const FIREFOX_PROFILES = `${APP_SUPPORT}/Firefox/`;
+  const MOZILLA = `${APP_SUPPORT}/Mozilla/`;
+  const CHROME = `${APP_SUPPORT}/Google/Chrome/`;
+
+  const FIREFOX_MANIFEST = `${APP_SUPPORT}/Mozilla/NativeMessagingHosts/com.8bit.bitwarden.json`;
+  const CHROME_MANIFEST = `${APP_SUPPORT}/Google/Chrome/NativeMessagingHosts/com.8bit.bitwarden.json`;
+
+  let logService: MockProxy<LogService>;
+  let sut: NativeMessagingMain;
+  let originalPlatform: PropertyDescriptor;
+
+  const givenOnDisk = (paths: string[]) => {
+    const present = new Set([BINARY_PATH, ...paths]);
+    (existsSync as jest.Mock).mockImplementation((candidate: string) => present.has(candidate));
+  };
+
+  const manifestWrittenTo = (destination: string) => {
+    const call = (fs.writeFile as jest.Mock).mock.calls.find(([target]) => target === destination);
+    return call == null ? undefined : JSON.parse(call[1]);
+  };
+
+  beforeEach(() => {
+    jest.clearAllMocks();
+
+    originalPlatform = Object.getOwnPropertyDescriptor(process, "platform");
+    Object.defineProperty(process, "platform", { value: "darwin", configurable: true });
+
+    (fs.mkdir as jest.Mock).mockResolvedValue(undefined);
+    (fs.writeFile as jest.Mock).mockResolvedValue(undefined);
+    (fs.unlink as jest.Mock).mockResolvedValue(undefined);
+
+    logService = mock<LogService>();
+    sut = new NativeMessagingMain(
+      logService,
+      mock<WindowMain>(),
+      "/user/path",
+      EXE_PATH,
+      "/app/path",
+    );
+  });
+
+  afterEach(() => {
+    Object.defineProperty(process, "platform", originalPlatform);
+  });
+
+  describe("generateManifests on macOS", () => {
+    it("installs the Firefox manifest when only the Firefox profile directory exists", async () => {
+      givenOnDisk([FIREFOX_PROFILES]);
+
+      await sut.generateManifests();
+
+      expect(fs.mkdir).toHaveBeenCalledWith(`${APP_SUPPORT}/Mozilla/NativeMessagingHosts`, {
+        recursive: true,
+      });
+      expect(manifestWrittenTo(FIREFOX_MANIFEST)).toEqual(
+        expect.objectContaining({
+          name: "com.8bit.bitwarden",
+          path: BINARY_PATH,
+          allowed_extensions: ["{446900e4-71c2-419f-a6a7-df9c091e268b}"],
+        }),
+      );
+    });
+
+    it("still installs the Firefox manifest when only Mozilla/ exists", async () => {
+      givenOnDisk([MOZILLA]);
+
+      await sut.generateManifests();
+
+      expect(manifestWrittenTo(FIREFOX_MANIFEST)).toBeDefined();
+    });
+
+    it("skips Firefox when neither the profile directory nor Mozilla/ exists", async () => {
+      givenOnDisk([CHROME]);
+
+      await sut.generateManifests();
+
+      expect(manifestWrittenTo(FIREFOX_MANIFEST)).toBeUndefined();
+      expect(logService.warning).toHaveBeenCalledWith("Firefox not found, skipping.");
+    });
+
+    it("installs a Chrome-flavoured manifest for chromium browsers", async () => {
+      givenOnDisk([CHROME]);
+
+      await sut.generateManifests();
+
+      expect(manifestWrittenTo(CHROME_MANIFEST)).toEqual(
+        expect.objectContaining({
+          allowed_origins: expect.arrayContaining([
+            "chrome-extension://nngceckbapebfimnlniiiahkandclblb/",
+          ]),
+        }),
+      );
+    });
+
+    it("still installs the other browsers when the Mozilla directory cannot be created", async () => {
+      givenOnDisk([FIREFOX_PROFILES, CHROME]);
+      (fs.mkdir as jest.Mock).mockImplementation((directory: string) =>
+        directory.includes("Mozilla")
+          ? Promise.reject(new Error("EPERM: operation not permitted"))
+          : Promise.resolve(undefined),
+      );
+
+      await expect(sut.generateManifests()).resolves.toBeUndefined();
+
+      expect(manifestWrittenTo(FIREFOX_MANIFEST)).toBeUndefined();
+      expect(manifestWrittenTo(CHROME_MANIFEST)).toBeDefined();
+      expect(logService.error).toHaveBeenCalledWith(expect.stringContaining("Firefox"));
+    });
+
+    it("still installs the other browsers when the Firefox manifest cannot be written", async () => {
+      givenOnDisk([FIREFOX_PROFILES, CHROME]);
+      (fs.writeFile as jest.Mock).mockImplementation((target: string) =>
+        target === FIREFOX_MANIFEST
+          ? Promise.reject(new Error("EACCES: permission denied"))
+          : Promise.resolve(undefined),
+      );
+
+      await expect(sut.generateManifests()).resolves.toBeUndefined();
+
+      expect(manifestWrittenTo(CHROME_MANIFEST)).toBeDefined();
+      expect(logService.error).toHaveBeenCalledWith(expect.stringContaining("Firefox"));
+    });
+  });
+
+  describe("removeManifests on macOS", () => {
+    it("removes the Firefox manifest from Mozilla/NativeMessagingHosts", async () => {
+      givenOnDisk([FIREFOX_MANIFEST]);
+
+      await sut.removeManifests();
+
+      expect(fs.unlink).toHaveBeenCalledWith(FIREFOX_MANIFEST);
+    });
+  });
+});
diff --git a/apps/desktop/src/main/native-messaging.main.ts b/apps/desktop/src/main/native-messaging.main.ts
index 0fb1e75b8b7f..838646b9b093 100644
--- a/apps/desktop/src/main/native-messaging.main.ts
+++ b/apps/desktop/src/main/native-messaging.main.ts
@@ -191,18 +191,25 @@ export class NativeMessagingMain {
       case "darwin": {
         const nmhs = this.getDarwinNMHS();
         for (const [key, browserDirectory] of Object.entries(nmhs)) {
-          if (existsSync(browserDirectory)) {
+          if (
+            this.getDarwinDetectPaths(key, browserDirectory).some((directory) =>
+              existsSync(directory),
+            )
+          ) {
             const nmhsPath = path.join(browserDirectory, "NativeMessagingHosts");
             const manifestPath = path.join(nmhsPath, "com.8bit.bitwarden.json");
 
-            let manifest: any = await this.generateChromeJson(binaryPath);
-            if (key === "Firefox" || key === "Zen") {
-              // Only generate the NMHS dir if the browser directory exists
-              await fs.mkdir(nmhsPath, { recursive: true });
-              manifest = await this.generateFirefoxJson(binaryPath);
-            }
+            try {
+              let manifest: any = await this.generateChromeJson(binaryPath);
+              if (key === "Firefox" || key === "Zen") {
+                await fs.mkdir(nmhsPath, { recursive: true });
+                manifest = await this.generateFirefoxJson(binaryPath);
+              }
 
-            await this.writeManifest(manifestPath, manifest);
+              await this.writeManifest(manifestPath, manifest);
+            } catch (e) {
+              this.logService.error(`Unable to install the ${key} manifest in ${nmhsPath}: ${e}`);
+            }
           } else {
             this.logService.warning(`${key} not found, skipping.`);
           }
@@ -416,6 +423,14 @@ export class NativeMessagingMain {
     /* eslint-enable no-useless-escape */
   }
 
+  private getDarwinDetectPaths(browser: string, browserDirectory: string): string[] {
+    if (browser === "Firefox") {
+      return [`${this.homedir()}/Library/Application Support/Firefox/`, browserDirectory];
+    }
+
+    return [browserDirectory];
+  }
+
   private getLinuxNMHS() {
     return {
       Firefox: `${this.homedir()}/.mozilla/`,