diff --git a/face_swapper/src/training.py b/face_swapper/src/training.py
index 4559bf6..63e439c 100644
--- a/face_swapper/src/training.py
+++ b/face_swapper/src/training.py
@@ -76,10 +76,15 @@ class FaceSwapperTrainer(lightning.LightningModule, FaceSwapperLoss):
 
 	def validation_step(self, batch : Batch, batch_index : int) -> Tensor:
 		source_tensor, target_tensor, _ = batch
-		source_embedding = calc_id_embedding(self.id_embedder, source_tensor, (0, 0, 0, 0))
-		output_tensor, target_attributes = self.generator(target_tensor, source_embedding)
-		output_embedding = calc_id_embedding(self.id_embedder, output_tensor, (0, 0, 0, 0))
-		validation = (nn.functional.cosine_similarity(source_embedding, output_embedding).mean() + 1) * 0.5
+
+		if torch.isnan(source_tensor).any() and torch.isnan(target_tensor).any():
+			source_embedding = calc_id_embedding(self.id_embedder, source_tensor, (0, 0, 0, 0))
+			output_tensor, target_attributes = self.generator(target_tensor, source_embedding)
+			output_embedding = calc_id_embedding(self.id_embedder, output_tensor, (0, 0, 0, 0))
+			validation = (nn.functional.cosine_similarity(source_embedding, output_embedding).mean() + 1) * 0.5
+		else:
+			validation = torch.tensor(0.0)
+
 		self.log('validation', validation)
 		return validation