diff --git a/mmrotate/core/post_processing/bbox_nms_rotated.py b/mmrotate/core/post_processing/bbox_nms_rotated.py
index 4affc2c9c..561ed5640 100644
--- a/mmrotate/core/post_processing/bbox_nms_rotated.py
+++ b/mmrotate/core/post_processing/bbox_nms_rotated.py
@@ -30,6 +30,9 @@ def multiclass_nms_rotated(multi_bboxes,
         tuple (dets, labels, indices (optional)): tensors of shape (k, 5), \
         (k), and (k). Dets are boxes with scores. Labels are 0-based.
     """
+    # --- Windows / FP16 safety fix ---
+    multi_bboxes = multi_bboxes.cpu()
+    multi_scores = multi_scores.cpu()
     num_classes = multi_scores.size(1) - 1
     # exclude background category
     if multi_bboxes.shape[1] > 5:
@@ -39,7 +42,7 @@ def multiclass_nms_rotated(multi_bboxes,
             multi_scores.size(0), num_classes, 5)
     scores = multi_scores[:, :-1]
 
-    labels = torch.arange(num_classes, dtype=torch.long, device=scores.device)
+    labels = torch.arange(num_classes, dtype=torch.long)
     labels = labels.view(1, -1).expand_as(scores)
     bboxes = bboxes.reshape(-1, 5)
     scores = scores.reshape(-1)
diff --git a/mmrotate/core/visualization/image.py b/mmrotate/core/visualization/image.py
index b042007d2..6e4eaf55f 100644
--- a/mmrotate/core/visualization/image.py
+++ b/mmrotate/core/visualization/image.py
@@ -139,6 +139,8 @@ def imshow_det_rbboxes(img,
         assert bboxes is not None and bboxes.shape[1] == 6
         scores = bboxes[:, -1]
         inds = scores > score_thr
+        if hasattr(inds, "to"):
+            inds = inds.to(bboxes.device)
         bboxes = bboxes[inds, :]
         labels = labels[inds]
         if segms is not None: