diff --git a/application/single_app/config.py b/application/single_app/config.py
index e01166f31..2ae26af44 100644
--- a/application/single_app/config.py
+++ b/application/single_app/config.py
@@ -96,7 +96,7 @@
 EXECUTOR_TYPE = 'thread'
 EXECUTOR_MAX_WORKERS = 30
 SESSION_TYPE = 'filesystem'
-VERSION = "0.250.195"
+VERSION = "0.250.196"
 IS_DEVELOPMENT = is_development_env_enabled()
 
 SESSION_COOKIE_SAMESITE = os.getenv('SESSION_COOKIE_SAMESITE', 'Lax')
diff --git a/application/single_app/templates/_top_nav.html b/application/single_app/templates/_top_nav.html
index 3d55f63d4..7fe55372b 100644
--- a/application/single_app/templates/_top_nav.html
+++ b/application/single_app/templates/_top_nav.html
@@ -1,5 +1,6 @@
 {% set is_chat_page = request.endpoint == 'frontend_chats.chats' %}
 {% set latest_features_nav_is_hidden = latest_features_nav_hidden | default(false) %}
+{% set public_workspace_labels = app_settings.public_workspace_labels %}
 <nav class="navbar navbar-expand-lg navbar-light bg-light fixed-top top-nav-bar{% if is_chat_page %} top-nav-bar-chat{% endif %}">
     <div class="container-fluid top-nav-shell{% if is_chat_page %} top-nav-shell-chat{% endif %}">
         <div class="top-nav-brand">
@@ -396,4 +397,3 @@ <h5 class="offcanvas-title" id="topNavMobileMenuLabel">Navigation</h5>
     </div>
 </div>
 {% endif %}
-{% set public_workspace_labels = app_settings.public_workspace_labels %}
diff --git a/docs/explanation/fixes/TOP_NAV_PUBLIC_WORKSPACE_LABEL_CRASH_FIX.md b/docs/explanation/fixes/TOP_NAV_PUBLIC_WORKSPACE_LABEL_CRASH_FIX.md
new file mode 100644
index 000000000..204398236
--- /dev/null
+++ b/docs/explanation/fixes/TOP_NAV_PUBLIC_WORKSPACE_LABEL_CRASH_FIX.md
@@ -0,0 +1,64 @@
+# Top Navigation Public Workspace Label Crash Fix
+
+Fixed/Implemented in version: **0.250.196**
+
+Version reference: `application/single_app/config.py` reports version `0.250.196`.
+
+## Issue Description
+
+Users could save the top navigation preference, but subsequent page requests returned a server error when Public Workspaces was enabled. Removing `"navLayout": "top"` from the user's Cosmos settings document allowed the application to render again because it restored the sidebar navigation path.
+
+## Root Cause Analysis
+
+The stored navigation preference was valid. It caused `base.html` to include `_top_nav.html`, where the signed-in user menu referenced `public_workspace_labels.plural` before the template assigned `public_workspace_labels`.
+
+Jinja treats an assignment in the template as a template-local variable. The earlier attribute lookup therefore raised `jinja2.exceptions.UndefinedError` instead of using the label context already available through `app_settings`. The sidebar navigation did not fail because it initialized the same variable before its first use.
+
+## Technical Details
+
+Files modified:
+
+- `application/single_app/templates/_top_nav.html`
+- `application/single_app/config.py`
+- `functional_tests/test_public_workspace_display_name_settings.py`
+- `ui_tests/test_chat_sidebar_toggle_controls.py`
+- `docs/explanation/fixes/TOP_NAV_PUBLIC_WORKSPACE_LABEL_CRASH_FIX.md`
+- `docs/explanation/release_notes.md`
+
+Code changes summary:
+
+- Moved the `public_workspace_labels` assignment to the top-navigation initialization block.
+- Preserved the existing `navLayout` setting, Cosmos document shape, navigation conditions, routes, and responsive behavior.
+- Added a deterministic render regression using the real top-navigation template with a signed-in user, Public Workspaces enabled, a custom label, and the persisted top-navigation preference.
+- Strengthened the authenticated browser workflow to verify that a page loaded with persisted top navigation returns successfully and exposes a usable user menu.
+
+Impact:
+
+- Users can select top navigation without becoming locked out of the application when Public Workspaces is enabled.
+- Default and customized Public Workspace labels continue to appear in the top-navigation user menu.
+- No settings migration or manual Cosmos profile repair is required after deployment.
+
+## Validation
+
+Testing approach:
+
+- Run `python functional_tests/test_public_workspace_display_name_settings.py`.
+- Run `pytest ui_tests/test_chat_sidebar_toggle_controls.py::test_chat_sidebar_desktop_uses_sidebar_toggle_without_inline_duplicate` against an authenticated UI environment.
+- Run `git -c core.whitespace=blank-at-eol,blank-at-eof,space-before-tab,cr-at-eol diff --check`.
+
+Test results:
+
+- The Public Workspace display-name functional test passed all four checks, including the real top-navigation render regression.
+- The changed Python test files passed syntax compilation.
+- The authenticated Playwright test was collected successfully and skipped because the local UI base URL and storage state were not configured.
+- The repository diff check passed.
+
+Before:
+
+- Rendering `_top_nav.html` for a signed-in user with Public Workspaces enabled raised `UndefinedError: 'public_workspace_labels' is undefined`.
+- Any page using the persisted top-navigation layout could return a server error.
+
+After:
+
+- The label context is initialized before any top-navigation branch reads it.
+- The same render path succeeds and includes the configured Public Workspace label.
diff --git a/docs/explanation/release_notes.md b/docs/explanation/release_notes.md
index befbf48cd..7ecaa7060 100644
--- a/docs/explanation/release_notes.md
+++ b/docs/explanation/release_notes.md
@@ -2,6 +2,15 @@
 
 For feature-focused and fix-focused drill-downs by version, see [Features by Version](/explanation/features/) and [Fixes by Version](/explanation/fixes/).
 
+### **(v0.250.196)**
+
+#### Bug Fixes
+
+*   **Top Navigation Public Workspace Lockout**
+    *   Fixed a server-rendering failure that could lock users out after they selected top navigation while Public Workspaces was enabled.
+    *   Preserved the saved navigation preference and default or customized Public Workspace labels without requiring a Cosmos profile repair.
+    *   (Ref: `_top_nav.html`, `test_public_workspace_display_name_settings.py`, `TOP_NAV_PUBLIC_WORKSPACE_LABEL_CRASH_FIX.md`)
+
 ### **(v0.250.185)**
 
 #### Bug Fixes
diff --git a/functional_tests/test_public_workspace_display_name_settings.py b/functional_tests/test_public_workspace_display_name_settings.py
index 1cede91a0..e36ef529d 100644
--- a/functional_tests/test_public_workspace_display_name_settings.py
+++ b/functional_tests/test_public_workspace_display_name_settings.py
@@ -1,16 +1,21 @@
 #!/usr/bin/env python3
 """
 Functional test for configurable Public Workspace end-user display names.
-Version: 0.250.110
+Version: 0.250.196
 Implemented in: 0.250.110
+Top-navigation crash regression added in: 0.250.196
 
 This test ensures that Public Workspace display-name settings are normalized,
-derived labels are safe for frontend use, and only the raw setting is persisted.
+derived labels are safe for frontend use, only the raw setting is persisted,
+and the top navigation can render those labels for signed-in users.
 """
 
 import ast
 import os
 import sys
+from types import SimpleNamespace
+
+from jinja2 import Environment
 
 sys.path.append(os.path.dirname(os.path.abspath(__file__)))
 
@@ -19,6 +24,7 @@
 ADMIN_ROUTE = os.path.join(REPO_ROOT, "application", "single_app", "route_frontend_admin_settings.py")
 ADMIN_TEMPLATE = os.path.join(REPO_ROOT, "application", "single_app", "templates", "admin_settings.html")
 BASE_TEMPLATE = os.path.join(REPO_ROOT, "application", "single_app", "templates", "base.html")
+TOP_NAV_TEMPLATE = os.path.join(REPO_ROOT, "application", "single_app", "templates", "_top_nav.html")
 
 
 def read_source(path):
@@ -122,6 +128,55 @@ def test_display_name_persistence_shape():
     return True
 
 
+def test_top_navigation_renders_public_workspace_labels():
+    """Validate persisted top navigation renders enabled Public Workspace labels."""
+    print("Testing top navigation Public Workspace label rendering...")
+    template_source = read_source(TOP_NAV_TEMPLATE)
+    app_settings = {
+        "show_logo": False,
+        "hide_app_title": False,
+        "app_title": "SimpleChat",
+        "enable_user_workspace": False,
+        "enable_group_workspaces": False,
+        "enable_public_workspaces": True,
+        "enable_custom_pages": False,
+        "enable_support_menu": False,
+        "enable_external_links": False,
+        "enable_user_feedback": False,
+        "enable_content_safety": False,
+        "require_member_of_control_center_admin": True,
+        "require_member_of_control_center_dashboard_reader": True,
+        "require_member_of_safety_violation_admin": True,
+        "require_member_of_feedback_admin": True,
+        "public_workspace_labels": {
+            "plural": "Knowledge Spaces",
+        },
+    }
+    rendered = Environment(autoescape=True).from_string(template_source).render(
+        request=SimpleNamespace(endpoint="frontend_workspace.workspace"),
+        session={
+            "user": {
+                "name": "Test User",
+                "roles": ["User"],
+            },
+        },
+        app_settings=app_settings,
+        user_settings={
+            "settings": {
+                "navLayout": "top",
+            },
+        },
+        latest_features_nav_hidden=False,
+        custom_pages_nav=[],
+        url_for=lambda endpoint, **kwargs: f"/{endpoint}",
+    )
+
+    assert '<nav class="navbar ' in rendered
+    assert "My Knowledge Spaces" in rendered
+    print("Top navigation Public Workspace label rendering passed.")
+    return True
+
+
 def test_admin_and_frontend_wiring():
     """Validate Admin Settings and frontend sanitized-label wiring."""
     print("Testing Public Workspace display-name wiring...")
@@ -179,6 +234,7 @@ def main():
     tests = [
         test_display_name_normalization,
         test_display_name_persistence_shape,
+        test_top_navigation_renders_public_workspace_labels,
         test_admin_and_frontend_wiring,
     ]
     results = []
diff --git a/ui_tests/test_chat_sidebar_toggle_controls.py b/ui_tests/test_chat_sidebar_toggle_controls.py
index ef3a4fbd3..ec2ff336f 100644
--- a/ui_tests/test_chat_sidebar_toggle_controls.py
+++ b/ui_tests/test_chat_sidebar_toggle_controls.py
@@ -1,8 +1,9 @@
 # test_chat_sidebar_toggle_controls.py
 """
 UI test for the unified chat navigation shell.
-Version: 0.241.018
+Version: 0.250.196
 Implemented in: 0.241.018
+Top-navigation crash regression added in: 0.250.196
 
 This test ensures that chats in top-nav mode use the adaptive conversation
 rail, preserve compact desktop top-nav links, and become the hamburger drawer
@@ -100,9 +101,14 @@ def test_chat_sidebar_desktop_uses_sidebar_toggle_without_inline_duplicate(playw
         expect(page.locator("#chat-sidebar-inline-toggle")).to_have_count(0)
         expect(page.locator("#floating-expand-btn")).to_have_count(0)
         expect(page.locator("#topNavMobileMenu")).to_have_count(0)
+        expect(page.locator("nav.top-nav-bar")).to_be_visible()
         expect(page.locator(".top-nav-chat-nav")).to_be_visible()
         expect(page.locator(".top-nav-chat-nav .nav-link").first).to_be_visible()
 
+        page.locator("#userDropdown").click()
+        expect(page.locator(".top-nav-user-menu.show")).to_be_visible()
+        page.locator("#userDropdown").click()
+
         sidebar_toggle.click()
         page.wait_for_function("document.body.classList.contains('sidebar-collapsed')")