diff --git a/apps/browser/src/popup/app-routing.module.ts b/apps/browser/src/popup/app-routing.module.ts
index eb64c076192..12e1288e806 100644
--- a/apps/browser/src/popup/app-routing.module.ts
+++ b/apps/browser/src/popup/app-routing.module.ts
@@ -68,6 +68,7 @@ import { popupRouterCacheGuard } from "../platform/popup/view-cache/popup-router
 import { RouteCacheOptions } from "../platform/services/popup-view-cache-background.service";
 import { CredentialGeneratorHistoryComponent } from "../tools/popup/generator/credential-generator-history.component";
 import { CredentialGeneratorComponent } from "../tools/popup/generator/credential-generator.component";
+import { firefoxPopoutGuard } from "../tools/popup/guards/firefox-popout.guard";
 import { SendAddEditComponent as SendAddEditV2Component } from "../tools/popup/send-v2/add-edit/send-add-edit.component";
 import { SendCreatedComponent } from "../tools/popup/send-v2/send-created/send-created.component";
 import { SendV2Component } from "../tools/popup/send-v2/send-v2.component";
@@ -262,7 +263,7 @@ const routes: Routes = [
   {
     path: "import",
     component: ImportBrowserV2Component,
-    canActivate: [authGuard],
+    canActivate: [authGuard, firefoxPopoutGuard()],
     data: { elevation: 1 } satisfies RouteDataProperties,
   },
   {
@@ -340,13 +341,13 @@ const routes: Routes = [
   {
     path: "add-send",
     component: SendAddEditV2Component,
-    canActivate: [authGuard],
+    canActivate: [authGuard, firefoxPopoutGuard()],
     data: { elevation: 1 } satisfies RouteDataProperties,
   },
   {
     path: "edit-send",
     component: SendAddEditV2Component,
-    canActivate: [authGuard],
+    canActivate: [authGuard, firefoxPopoutGuard()],
     data: { elevation: 1 } satisfies RouteDataProperties,
   },
   {
diff --git a/apps/browser/src/tools/popup/guards/firefox-popout.guard.spec.ts b/apps/browser/src/tools/popup/guards/firefox-popout.guard.spec.ts
new file mode 100644
index 00000000000..df04b965d4c
--- /dev/null
+++ b/apps/browser/src/tools/popup/guards/firefox-popout.guard.spec.ts
@@ -0,0 +1,194 @@
+import { TestBed } from "@angular/core/testing";
+import { ActivatedRouteSnapshot, RouterStateSnapshot } from "@angular/router";
+
+import { DeviceType } from "@bitwarden/common/enums";
+
+import { BrowserApi } from "../../../platform/browser/browser-api";
+import BrowserPopupUtils from "../../../platform/browser/browser-popup-utils";
+import { BrowserPlatformUtilsService } from "../../../platform/services/platform-utils/browser-platform-utils.service";
+
+import { firefoxPopoutGuard } from "./firefox-popout.guard";
+
+describe("firefoxPopoutGuard", () => {
+  let getDeviceSpy: jest.SpyInstance;
+  let inPopoutSpy: jest.SpyInstance;
+  let inSidebarSpy: jest.SpyInstance;
+  let openPopoutSpy: jest.SpyInstance;
+  let closePopupSpy: jest.SpyInstance;
+
+  const mockRoute = {} as ActivatedRouteSnapshot;
+  const mockState: RouterStateSnapshot = {
+    url: "/import?param=value",
+  } as RouterStateSnapshot;
+
+  beforeEach(() => {
+    getDeviceSpy = jest.spyOn(BrowserPlatformUtilsService, "getDevice");
+    inPopoutSpy = jest.spyOn(BrowserPopupUtils, "inPopout");
+    inSidebarSpy = jest.spyOn(BrowserPopupUtils, "inSidebar");
+    openPopoutSpy = jest.spyOn(BrowserPopupUtils, "openPopout").mockImplementation();
+    closePopupSpy = jest.spyOn(BrowserApi, "closePopup").mockImplementation();
+
+    TestBed.configureTestingModule({});
+  });
+
+  afterEach(() => {
+    jest.clearAllMocks();
+  });
+
+  describe("when browser is Firefox", () => {
+    beforeEach(() => {
+      getDeviceSpy.mockReturnValue(DeviceType.FirefoxExtension);
+      inPopoutSpy.mockReturnValue(false);
+      inSidebarSpy.mockReturnValue(false);
+    });
+
+    it("should open popout and block navigation when not already in popout or sidebar", async () => {
+      const guard = firefoxPopoutGuard();
+      const result = await TestBed.runInInjectionContext(() => guard(mockRoute, mockState));
+
+      expect(getDeviceSpy).toHaveBeenCalledWith(window);
+      expect(inPopoutSpy).toHaveBeenCalledWith(window);
+      expect(inSidebarSpy).toHaveBeenCalledWith(window);
+      expect(openPopoutSpy).toHaveBeenCalledWith("popup/index.html#/import?param=value");
+      expect(closePopupSpy).toHaveBeenCalledWith(window);
+      expect(result).toBe(false);
+    });
+
+    it("should not add autoClosePopout parameter to the url", async () => {
+      const guard = firefoxPopoutGuard();
+      await TestBed.runInInjectionContext(() => guard(mockRoute, mockState));
+
+      expect(openPopoutSpy).toHaveBeenCalledWith("popup/index.html#/import?param=value");
+      expect(openPopoutSpy).not.toHaveBeenCalledWith(expect.stringContaining("autoClosePopout"));
+    });
+
+    it("should allow navigation when already in popout", async () => {
+      inPopoutSpy.mockReturnValue(true);
+
+      const guard = firefoxPopoutGuard();
+      const result = await TestBed.runInInjectionContext(() => guard(mockRoute, mockState));
+
+      expect(openPopoutSpy).not.toHaveBeenCalled();
+      expect(closePopupSpy).not.toHaveBeenCalled();
+      expect(result).toBe(true);
+    });
+
+    it("should allow navigation when already in sidebar", async () => {
+      inSidebarSpy.mockReturnValue(true);
+
+      const guard = firefoxPopoutGuard();
+      const result = await TestBed.runInInjectionContext(() => guard(mockRoute, mockState));
+
+      expect(openPopoutSpy).not.toHaveBeenCalled();
+      expect(closePopupSpy).not.toHaveBeenCalled();
+      expect(result).toBe(true);
+    });
+  });
+
+  describe("when browser is not Firefox", () => {
+    beforeEach(() => {
+      inPopoutSpy.mockReturnValue(false);
+      inSidebarSpy.mockReturnValue(false);
+    });
+
+    it.each([
+      { deviceType: DeviceType.ChromeExtension, name: "ChromeExtension" },
+      { deviceType: DeviceType.EdgeExtension, name: "EdgeExtension" },
+      { deviceType: DeviceType.OperaExtension, name: "OperaExtension" },
+      { deviceType: DeviceType.SafariExtension, name: "SafariExtension" },
+      { deviceType: DeviceType.VivaldiExtension, name: "VivaldiExtension" },
+    ])(
+      "should allow navigation without opening popout when device is $name",
+      async ({ deviceType }) => {
+        getDeviceSpy.mockReturnValue(deviceType);
+
+        const guard = firefoxPopoutGuard();
+        const result = await TestBed.runInInjectionContext(() => guard(mockRoute, mockState));
+
+        expect(getDeviceSpy).toHaveBeenCalledWith(window);
+        expect(openPopoutSpy).not.toHaveBeenCalled();
+        expect(closePopupSpy).not.toHaveBeenCalled();
+        expect(result).toBe(true);
+      },
+    );
+  });
+
+  describe("file picker routes", () => {
+    beforeEach(() => {
+      getDeviceSpy.mockReturnValue(DeviceType.FirefoxExtension);
+      inPopoutSpy.mockReturnValue(false);
+      inSidebarSpy.mockReturnValue(false);
+    });
+
+    it("should open popout for /import route", async () => {
+      const importState: RouterStateSnapshot = {
+        url: "/import",
+      } as RouterStateSnapshot;
+
+      const guard = firefoxPopoutGuard();
+      const result = await TestBed.runInInjectionContext(() => guard(mockRoute, importState));
+
+      expect(openPopoutSpy).toHaveBeenCalledWith("popup/index.html#/import");
+      expect(closePopupSpy).toHaveBeenCalledWith(window);
+      expect(result).toBe(false);
+    });
+
+    it("should open popout for /add-send route", async () => {
+      const addSendState: RouterStateSnapshot = {
+        url: "/add-send",
+      } as RouterStateSnapshot;
+
+      const guard = firefoxPopoutGuard();
+      const result = await TestBed.runInInjectionContext(() => guard(mockRoute, addSendState));
+
+      expect(openPopoutSpy).toHaveBeenCalledWith("popup/index.html#/add-send");
+      expect(closePopupSpy).toHaveBeenCalledWith(window);
+      expect(result).toBe(false);
+    });
+
+    it("should open popout for /edit-send route", async () => {
+      const editSendState: RouterStateSnapshot = {
+        url: "/edit-send",
+      } as RouterStateSnapshot;
+
+      const guard = firefoxPopoutGuard();
+      const result = await TestBed.runInInjectionContext(() => guard(mockRoute, editSendState));
+
+      expect(openPopoutSpy).toHaveBeenCalledWith("popup/index.html#/edit-send");
+      expect(closePopupSpy).toHaveBeenCalledWith(window);
+      expect(result).toBe(false);
+    });
+  });
+
+  describe("url handling", () => {
+    beforeEach(() => {
+      getDeviceSpy.mockReturnValue(DeviceType.FirefoxExtension);
+      inPopoutSpy.mockReturnValue(false);
+      inSidebarSpy.mockReturnValue(false);
+    });
+
+    it("should preserve query parameters in the popout url", async () => {
+      const stateWithQuery: RouterStateSnapshot = {
+        url: "/import?foo=bar&baz=qux",
+      } as RouterStateSnapshot;
+
+      const guard = firefoxPopoutGuard();
+      await TestBed.runInInjectionContext(() => guard(mockRoute, stateWithQuery));
+
+      expect(openPopoutSpy).toHaveBeenCalledWith("popup/index.html#/import?foo=bar&baz=qux");
+      expect(closePopupSpy).toHaveBeenCalledWith(window);
+    });
+
+    it("should handle urls without query parameters", async () => {
+      const stateWithoutQuery: RouterStateSnapshot = {
+        url: "/simple-path",
+      } as RouterStateSnapshot;
+
+      const guard = firefoxPopoutGuard();
+      await TestBed.runInInjectionContext(() => guard(mockRoute, stateWithoutQuery));
+
+      expect(openPopoutSpy).toHaveBeenCalledWith("popup/index.html#/simple-path");
+      expect(closePopupSpy).toHaveBeenCalledWith(window);
+    });
+  });
+});
diff --git a/apps/browser/src/tools/popup/guards/firefox-popout.guard.ts b/apps/browser/src/tools/popup/guards/firefox-popout.guard.ts
new file mode 100644
index 00000000000..821f1b7a5bc
--- /dev/null
+++ b/apps/browser/src/tools/popup/guards/firefox-popout.guard.ts
@@ -0,0 +1,38 @@
+import { ActivatedRouteSnapshot, CanActivateFn, RouterStateSnapshot } from "@angular/router";
+
+import { BrowserApi } from "@bitwarden/browser/platform/browser/browser-api";
+import BrowserPopupUtils from "@bitwarden/browser/platform/browser/browser-popup-utils";
+import { BrowserPlatformUtilsService } from "@bitwarden/browser/platform/services/platform-utils/browser-platform-utils.service";
+import { DeviceType } from "@bitwarden/common/enums";
+
+/**
+ * Guard that forces a popout window on Firefox browser when a file picker could be exposed.
+ * Necessary to avoid a crash: https://bugzilla.mozilla.org/show_bug.cgi?id=1292701
+ * Also disallows the user from closing a popout and re-opening the view exposing the file picker.
+ *
+ * @returns CanActivateFn that opens popout and blocks navigation on Firefox
+ */
+export function firefoxPopoutGuard(): CanActivateFn {
+  return async (_route: ActivatedRouteSnapshot, state: RouterStateSnapshot) => {
+    // Check if browser is Firefox using the platform utils service
+    const deviceType = BrowserPlatformUtilsService.getDevice(window);
+    const isFirefox = deviceType === DeviceType.FirefoxExtension;
+
+    // Check if already in popout/sidebar
+    const inPopout = BrowserPopupUtils.inPopout(window);
+    const inSidebar = BrowserPopupUtils.inSidebar(window);
+
+    // Open popout if on Firefox and not already in popout/sidebar
+    if (isFirefox && !inPopout && !inSidebar) {
+      // Don't add autoClosePopout for file picker scenarios - user should manually close
+      await BrowserPopupUtils.openPopout(`popup/index.html#${state.url}`);
+
+      // Close the original popup window
+      BrowserApi.closePopup(window);
+
+      return false; // Block navigation - popout will reload
+    }
+
+    return true; // Allow navigation
+  };
+}