diff --git a/tests/preferences/test_clear_cookie_data.py b/tests/preferences/test_clear_cookie_data.py
index 512f2beef..614c76967 100644
--- a/tests/preferences/test_clear_cookie_data.py
+++ b/tests/preferences/test_clear_cookie_data.py
@@ -1,8 +1,6 @@
-import sys
-from os import environ
-
 import pytest
 from selenium.webdriver import Firefox
+from selenium.webdriver.support.ui import WebDriverWait
 
 from modules.page_object import AboutPrefs
 from modules.util import BrowserActions
@@ -12,38 +10,71 @@
 def test_case():
     return "143627"
 
+WEBSITE_ADDRESS = "https://www.wikipedia.com"
+#WIN_GHA = environ.get("GITHUB_ACTIONS") == "true" and sys.platform.startswith("win")
+
 
-WIN_GHA = environ.get("GITHUB_ACTIONS") == "true" and sys.platform.startswith("win")
+def _dialog_options_present(about_prefs: AboutPrefs) -> bool:
+    """Return True when the Clear Data dialog options container exists."""
+    try:
+        about_prefs.get_element("clear-data-dialog-options")
+        return True
+    except Exception:
+        return False
 
 
-def open_clear_cookies_data_dialog(about_prefs: AboutPrefs, ba: BrowserActions):
+def open_clear_cookies_data_dialog(about_prefs: AboutPrefs, ba: BrowserActions, wait: WebDriverWait):
+    """
+    Open about:preferences#privacy, show 'Clear Data' dialog, switch into its iframe,
+    wait for its options container to be present, read the value, then switch back.
+    """
     about_prefs.open()
-    clear_data_popup = about_prefs.press_button_get_popup_dialog_iframe("Clear Data")
-    ba.switch_to_iframe_context(clear_data_popup)
-    return about_prefs.get_clear_cookie_data_value()
 
+    # Click the button and grab the dialog iframe element
+    dlg_iframe = about_prefs.press_button_get_popup_dialog_iframe("Clear Data")
+
+    # Wait until the iframe is attached and visible before switching
+    wait.until(lambda _: dlg_iframe and dlg_iframe.is_displayed())
+
+    # Enter dialog iframe
+    ba.switch_to_iframe_context(dlg_iframe)
 
-@pytest.mark.skipif(WIN_GHA, reason="Test unstable in Windows GA, tracked in 1990570")
+    # Wait for dialog content to be ready (no custom timeout kwarg)
+    wait.until(lambda _: _dialog_options_present(about_prefs))
+
+    value = about_prefs.get_clear_cookie_data_value()
+
+    # Always return to content context
+    ba.switch_to_content_context()
+    return value
+
+
+# @pytest.mark.skipif(WIN_GHA, reason="Test unstable in Windows GA, tracked in 1990570")
 def test_clear_cookie_data(driver: Firefox):
     """
     C143627: Cookies and site data can be cleared via the "Clear Data" panel
     """
-    # Instantiate objects
     about_prefs = AboutPrefs(driver, category="privacy")
     ba = BrowserActions(driver)
+    wait = WebDriverWait(driver, 20, poll_frequency=0.5)
 
     # Visit a site to get a cookie added to saved data
-    driver.get("https://www.wikipedia.com")
+    driver.get(WEBSITE_ADDRESS)
 
-    # Navigate to the clear data dialog of about:preferences#privacy
-    # Check for a non-zero value of the 'Cookies and site data' option
-    cookie_value = open_clear_cookies_data_dialog(about_prefs, ba)
-    assert cookie_value > 0
+    # Open dialog and read current value (must be > 0)
+    cookie_value = open_clear_cookies_data_dialog(about_prefs, ba, wait)
+    assert cookie_value > 0, f"Expected cookie/site data > 0, got {cookie_value}"
 
-    # Then clear the cookies and site data
+    # Clear cookies and site data: open dialog again, wait for iframe, click clear
+    about_prefs.open()
+    dlg_iframe = about_prefs.press_button_get_popup_dialog_iframe("Clear Data")
+    wait.until(lambda _: dlg_iframe and dlg_iframe.is_displayed())
+    ba.switch_to_iframe_context(dlg_iframe)
     about_prefs.get_element("clear-data-accept-button").click()
+    ba.switch_to_content_context()
 
-    # Finally, check the value of the dialog option, it should be 0
+    # Wait until the dialog reports 0 (reopen/poll via helper)
+    wait.until(lambda _: open_clear_cookies_data_dialog(about_prefs, ba, wait) == 0)
 
-    cookie_value2 = open_clear_cookies_data_dialog(about_prefs, ba)
-    assert cookie_value2 == 0
+    final_value = open_clear_cookies_data_dialog(about_prefs, ba, wait)
+    assert final_value == 0, f"Expected 0 after clearing, got {final_value}"