diff --git a/detect.py b/detect.py
index 0b1d938..8acd5bf 100644
--- a/detect.py
+++ b/detect.py
@@ -21,8 +21,9 @@ sys.path.append(FILE.parents[0].as_posix())  # add yolov5/ to path
 
 from models.experimental import attempt_load
 from utils.datasets import LoadStreams, LoadImages
-from utils.general import check_img_size, check_requirements, check_imshow, colorstr, is_ascii, non_max_suppression, \
-    apply_classifier, scale_coords, xyxy2xywh, strip_optimizer, set_logging, increment_path, save_one_box
+from utils.general import check_img_size, check_imshow, check_requirements, check_suffix, colorstr, is_ascii, \
+    non_max_suppression, apply_classifier, scale_coords, xyxy2xywh, strip_optimizer, set_logging, increment_path, \
+    save_one_box
 from utils.plots import Annotator, colors
 from utils.torch_utils import select_device, load_classifier, time_sync
 
@@ -68,8 +69,9 @@ def run(weights='yolov5s.pt',  # model.pt path(s)
 
     # Load model
     w = weights[0] if isinstance(weights, list) else weights
-    classify, suffix = False, Path(w).suffix.lower()
-    pt, onnx, tflite, pb, saved_model = (suffix == x for x in ['.pt', '.onnx', '.tflite', '.pb', ''])  # backend
+    classify, suffix, suffixes = False, Path(w).suffix.lower(), ['.pt', '.onnx', '.tflite', '.pb', '']
+    check_suffix(w, suffixes)  # check weights have acceptable suffix
+    pt, onnx, tflite, pb, saved_model = (suffix == x for x in suffixes)  # backend booleans
     stride, names = 64, [f'class{i}' for i in range(1000)]  # assign defaults
     if pt:
         model = attempt_load(weights, map_location=device)  # load FP32 model
diff --git a/models/tf.py b/models/tf.py
index 40e7d20..d6d0f26 100644
--- a/models/tf.py
+++ b/models/tf.py
@@ -53,7 +53,7 @@ from models.common import Conv, Bottleneck, SPP, DWConv, Focus, BottleneckCSP, C
 from models.experimental import MixConv2d, CrossConv, attempt_load
 from models.yolo import Detect
 from utils.datasets import LoadImages
-from utils.general import make_divisible, check_file, check_dataset
+from utils.general import check_dataset, check_yaml, make_divisible
 
 logger = logging.getLogger(__name__)
 
@@ -447,7 +447,7 @@ if __name__ == "__main__":
     parser.add_argument('--iou-thres', type=float, default=0.5, help='IOU threshold for NMS')
     parser.add_argument('--score-thres', type=float, default=0.4, help='score threshold for NMS')
     opt = parser.parse_args()
-    opt.cfg = check_file(opt.cfg)  # check file
+    opt.cfg = check_yaml(opt.cfg)  # check YAML
     opt.img_size *= 2 if len(opt.img_size) == 1 else 1  # expand
     print(opt)
 
@@ -534,7 +534,7 @@ if __name__ == "__main__":
             if opt.tfl_int8:
                 # Representative Dataset
                 if opt.source.endswith('.yaml'):
-                    with open(check_file(opt.source)) as f:
+                    with open(check_yaml(opt.source)) as f:
                         data = yaml.load(f, Loader=yaml.FullLoader)  # data dict
                         check_dataset(data)  # check
                     opt.source = data['train']
diff --git a/models/yolo.py b/models/yolo.py
index 8618401..25118a9 100644
--- a/models/yolo.py
+++ b/models/yolo.py
@@ -17,10 +17,10 @@ sys.path.append(FILE.parents[1].as_posix())  # add yolov5/ to path
 from models.common import *
 from models.experimental import *
 from utils.autoanchor import check_anchor_order
-from utils.general import make_divisible, check_file, set_logging
+from utils.general import check_yaml, make_divisible, set_logging
 from utils.plots import feature_visualization
-from utils.torch_utils import time_sync, fuse_conv_and_bn, model_info, scale_img, initialize_weights, \
-    select_device, copy_attr
+from utils.torch_utils import copy_attr, fuse_conv_and_bn, initialize_weights, model_info, scale_img, \
+    select_device, time_sync
 
 try:
     import thop  # for FLOPs computation
@@ -281,7 +281,7 @@ if __name__ == '__main__':
     parser.add_argument('--device', default='', help='cuda device, i.e. 0 or 0,1,2,3 or cpu')
     parser.add_argument('--profile', action='store_true', help='profile model speed')
     opt = parser.parse_args()
-    opt.cfg = check_file(opt.cfg)  # check file
+    opt.cfg = check_yaml(opt.cfg)  # check YAML
     set_logging()
     device = select_device(opt.device)
 
diff --git a/train.py b/train.py
index f9aa3d4..c326648 100644
--- a/train.py
+++ b/train.py
@@ -35,8 +35,8 @@ from models.yolo import Model
 from utils.autoanchor import check_anchors
 from utils.datasets import create_dataloader
 from utils.general import labels_to_class_weights, increment_path, labels_to_image_weights, init_seeds, \
-    strip_optimizer, get_latest_run, check_dataset, check_file, check_git_status, check_img_size, \
-    check_requirements, print_mutation, set_logging, one_cycle, colorstr, methods
+    strip_optimizer, get_latest_run, check_dataset, check_git_status, check_img_size, check_requirements, \
+    check_yaml, check_suffix, print_mutation, set_logging, one_cycle, colorstr, methods
 from utils.downloads import attempt_download
 from utils.loss import ComputeLoss
 from utils.plots import plot_labels, plot_evolve
@@ -484,7 +484,8 @@ def main(opt, callbacks=Callbacks()):
         opt.cfg, opt.weights, opt.resume = '', ckpt, True  # reinstate
         LOGGER.info(f'Resuming training from {ckpt}')
     else:
-        opt.data, opt.cfg, opt.hyp = check_file(opt.data), check_file(opt.cfg), check_file(opt.hyp)  # check files
+        check_suffix(opt.weights, '.pt')  # check weights
+        opt.data, opt.cfg, opt.hyp = check_yaml(opt.data), check_yaml(opt.cfg), check_yaml(opt.hyp)  # check YAMLs
         assert len(opt.cfg) or len(opt.weights), 'either --cfg or --weights must be specified'
         if opt.evolve:
             opt.project = 'runs/evolve'
diff --git a/utils/datasets.py b/utils/datasets.py
index 852bb7c..0c6b9b5 100755
--- a/utils/datasets.py
+++ b/utils/datasets.py
@@ -26,8 +26,8 @@ from torch.utils.data import Dataset
 from tqdm import tqdm
 
 from utils.augmentations import Albumentations, augment_hsv, copy_paste, letterbox, mixup, random_perspective
-from utils.general import check_requirements, check_file, check_dataset, xywh2xyxy, xywhn2xyxy, xyxy2xywhn, \
-    xyn2xy, segments2boxes, clean_str
+from utils.general import check_dataset, check_requirements, check_yaml, clean_str, segments2boxes, \
+    xywh2xyxy, xywhn2xyxy, xyxy2xywhn, xyn2xy
 from utils.torch_utils import torch_distributed_zero_first
 
 # Parameters
@@ -938,7 +938,7 @@ def dataset_stats(path='coco128.yaml', autodownload=False, verbose=False, profil
         im.save(im_dir / Path(f).name, quality=75)  # save
 
     zipped, data_dir, yaml_path = unzip(Path(path))
-    with open(check_file(yaml_path), errors='ignore') as f:
+    with open(check_yaml(yaml_path), errors='ignore') as f:
         data = yaml.safe_load(f)  # data dict
         if zipped:
             data['path'] = data_dir  # TODO: should this be dir.resolve()?
diff --git a/utils/general.py b/utils/general.py
index cc316cd..06c62da 100755
--- a/utils/general.py
+++ b/utils/general.py
@@ -242,8 +242,23 @@ def check_imshow():
         return False
 
 
-def check_file(file):
+def check_suffix(file='yolov5s.pt', suffix=('.pt',), msg=''):
+    # Check file(s) for acceptable suffixes
+    if any(suffix):
+        if isinstance(suffix, str):
+            suffix = [suffix]
+        for f in file if isinstance(file, (list, tuple)) else [file]:
+            assert Path(f).suffix.lower() in suffix, f"{msg}{f} acceptable suffix is {suffix}"
+
+
+def check_yaml(file, suffix=('.yaml', '.yml')):
+    # Check YAML file(s) for acceptable suffixes
+    return check_file(file, suffix)
+
+
+def check_file(file, suffix=''):
     # Search/download file (if necessary) and return path
+    check_suffix(file, suffix)
     file = str(file)  # convert to str()
     if Path(file).is_file() or file == '':  # exists
         return file
diff --git a/val.py b/val.py
index 947cd78..b7068e0 100644
--- a/val.py
+++ b/val.py
@@ -22,8 +22,9 @@ sys.path.append(FILE.parents[0].as_posix())  # add yolov5/ to path
 
 from models.experimental import attempt_load
 from utils.datasets import create_dataloader
-from utils.general import coco80_to_coco91_class, check_dataset, check_file, check_img_size, check_requirements, \
-    box_iou, non_max_suppression, scale_coords, xyxy2xywh, xywh2xyxy, set_logging, increment_path, colorstr
+from utils.general import coco80_to_coco91_class, check_dataset, check_img_size, check_requirements, \
+    check_suffix, check_yaml, box_iou, non_max_suppression, scale_coords, xyxy2xywh, xywh2xyxy, set_logging, \
+    increment_path, colorstr
 from utils.metrics import ap_per_class, ConfusionMatrix
 from utils.plots import plot_images, output_to_target, plot_study_txt
 from utils.torch_utils import select_device, time_sync
@@ -116,6 +117,7 @@ def run(data,
         (save_dir / 'labels' if save_txt else save_dir).mkdir(parents=True, exist_ok=True)  # make dir
 
         # Load model
+        check_suffix(weights, '.pt')
         model = attempt_load(weights, map_location=device)  # load FP32 model
         gs = max(int(model.stride.max()), 32)  # grid size (max stride)
         imgsz = check_img_size(imgsz, s=gs)  # check image size
@@ -316,7 +318,7 @@ def parse_opt():
     opt = parser.parse_args()
     opt.save_json |= opt.data.endswith('coco.yaml')
     opt.save_txt |= opt.save_hybrid
-    opt.data = check_file(opt.data)  # check file
+    opt.data = check_yaml(opt.data)  # check YAML
     return opt