diff --git a/mkdocs_exporter/formats/pdf/browser.py b/mkdocs_exporter/formats/pdf/browser.py
index 7ab7c57..9a34206 100644
--- a/mkdocs_exporter/formats/pdf/browser.py
+++ b/mkdocs_exporter/formats/pdf/browser.py
@@ -35,7 +35,14 @@ def __init__(self, options: dict = {}):
     self.context = None
     self._launched = False
     self.playwright = None
-    self.lock = asyncio.Lock()
+    try:
+      self.lock = asyncio.Lock()
+    except RuntimeError as e:
+      if 'no current event loop' in str(e):
+        asyncio.set_event_loop(asyncio.new_event_loop())
+        self.lock = asyncio.Lock()
+      else:
+        raise
     self.debug = options.get('debug', False)
     self.headless = options.get('headless', True)
     self.timeout = options.get('timeout', 60_000)
diff --git a/mkdocs_exporter/formats/pdf/plugin.py b/mkdocs_exporter/formats/pdf/plugin.py
index 6109ae0..08ad056 100644
--- a/mkdocs_exporter/formats/pdf/plugin.py
+++ b/mkdocs_exporter/formats/pdf/plugin.py
@@ -184,10 +184,15 @@ async def render(page: Page) -> None:
 
     for page in self.pages:
       self.aggregator.append(page.formats['pdf']['path'] + '.aggregate')
-      os.unlink(page.formats['pdf']['path'] + '.aggregate')
 
     self.aggregator.save()
 
+    for page in self.pages:
+      try:
+        os.unlink(page.formats['pdf']['path'] + '.aggregate')
+      except FileNotFoundError:
+        pass
+
 
   @event_priority(-100)
   def _on_post_build_3(self, **kwargs) -> None:
@@ -225,6 +230,8 @@ def flatten(items):
 
     for index, page in enumerate(self.pages):
       page.index = index
+      if not hasattr(page, 'formats'):
+        page.formats = {}
 
 
   def _enabled(self, page: Page = None) -> bool: