diff --git a/backend/main.py b/backend/main.py
index 8a3a1e5..405656f 100644
--- a/backend/main.py
+++ b/backend/main.py
@@ -1348,7 +1348,7 @@ async def api_file_pdf(vault_name: str, path: str = Query(..., description="Rela
     title = post.metadata.get("title", file_path.stem)
     pdf_html = build_pdf_html(html, str(title))
     pdf_bytes = generate_pdf(pdf_html, str(title))
-    safe_name = "".join(c for c in str(title) if c.isalnum() or c in " _-.").strip() or "document"
+    safe_name = "".join(c for c in str(title) if c.isascii() and (c.isalnum() or c in " _-.")).strip() or "document"
     return Response(content=pdf_bytes, media_type="application/pdf", headers={"Content-Disposition": f'attachment; filename="{safe_name}.pdf"'})
 
 
@@ -3811,7 +3811,7 @@ async def public_share_pdf_download(token: str):
     title = post.metadata.get("title", file_path.stem)
     pdf_html = build_pdf_html(html, str(title))
     pdf_bytes = generate_pdf(pdf_html, str(title))
-    safe_name = "".join(c for c in str(title) if c.isalnum() or c in " _-.").strip() or "document"
+    safe_name = "".join(c for c in str(title) if c.isascii() and (c.isalnum() or c in " _-.")).strip() or "document"
     return Response(content=pdf_bytes, media_type="application/pdf", headers={"Content-Disposition": f'attachment; filename="{safe_name}.pdf"'})