diff --git a/api/onnx_web/convert/diffusion/diffusion.py b/api/onnx_web/convert/diffusion/diffusion.py
index a8ecbbf7..ade270c0 100644
--- a/api/onnx_web/convert/diffusion/diffusion.py
+++ b/api/onnx_web/convert/diffusion/diffusion.py
@@ -381,7 +381,8 @@ def convert_diffusion_diffusers(
 
     if replace_vae is not None:
         vae_path = path.join(conversion.model_path, replace_vae)
-        if check_ext(replace_vae, RESOLVE_FORMATS):
+        vae_file = check_ext(replace_vae, RESOLVE_FORMATS)
+        if vae_file[0]:
             pipeline.vae = AutoencoderKL.from_single_file(vae_path)
         else:
             pipeline.vae = AutoencoderKL.from_pretrained(vae_path)
diff --git a/api/onnx_web/convert/diffusion/diffusion_xl.py b/api/onnx_web/convert/diffusion/diffusion_xl.py
index 18fa8493..26f50bd8 100644
--- a/api/onnx_web/convert/diffusion/diffusion_xl.py
+++ b/api/onnx_web/convert/diffusion/diffusion_xl.py
@@ -64,7 +64,8 @@ def convert_diffusion_diffusers_xl(
 
     if replace_vae is not None:
         vae_path = path.join(conversion.model_path, replace_vae)
-        if check_ext(vae_path, RESOLVE_FORMATS):
+        vae_file = check_ext(vae_path, RESOLVE_FORMATS)
+        if vae_file[0]:
             logger.debug("loading VAE from single tensor file: %s", vae_path)
             pipeline.vae = AutoencoderKL.from_single_file(vae_path)
         else: