diff --git a/great_ai/large_file/large_file/large_file_base.py b/great_ai/large_file/large_file/large_file_base.py
index 005f185..64138c5 100644
--- a/great_ai/large_file/large_file/large_file_base.py
+++ b/great_ai/large_file/large_file/large_file_base.py
@@ -64,7 +64,13 @@ class LargeFileBase(ABC):
         keep_last_n: Optional[int] = None,
         cache_only_mode: bool = False,
     ):
-        self._name = re.sub(r"[^a-zA-Z0-9._-]+", "", name)
+        clean_name = re.sub(r"[^!a-zA-Z0-9._-]+", "", name)
+        if clean_name != name:
+            raise ValueError(
+                f"Given name contains illegal characters, consider changing it to: `{clean_name}`"
+            )
+
+        self._name = name
         self._version = version
         self._mode = mode
         self._keep_last_n = keep_last_n
diff --git a/great_ai/large_file/large_file/large_file_mongo.py b/great_ai/large_file/large_file/large_file_mongo.py
index 3cbb9c0..3bed0a1 100644
--- a/great_ai/large_file/large_file/large_file_mongo.py
+++ b/great_ai/large_file/large_file/large_file_mongo.py
@@ -44,7 +44,7 @@ class LargeFileMongo(LargeFileBase):
     def _client(self) -> GridFSBucket:
         if self.mongo_connection_string is None or self.mongo_database is None:
             raise ValueError(
-                "Please configure the MongoDB access options by calling LargeFileMongo.configure_credentials or set offline_mode=True in the constructor."
+                "Please configure the MongoDB access options by calling LargeFileMongo.configure_credentials or set cache_only_mode=True in the constructor."
             )
 
         db: Database = MongoClient(self.mongo_connection_string)[self.mongo_database]
diff --git a/great_ai/large_file/large_file/large_file_s3.py b/great_ai/large_file/large_file/large_file_s3.py
index eb2a307..119caa8 100644
--- a/great_ai/large_file/large_file/large_file_s3.py
+++ b/great_ai/large_file/large_file/large_file_s3.py
@@ -56,7 +56,7 @@ class LargeFileS3(LargeFileBase):
             or self.bucket_name is None
         ):
             raise ValueError(
-                "Please configure the S3 access options by calling LargeFileS3.configure_credentials or set offline_mode=True in the constructor."
+                "Please configure the S3 access options by calling LargeFileS3.configure_credentials or set cache_only_mode=True in the constructor."
             )
 
         return boto3.client(
diff --git a/tests/large_file/test_large_file.py b/tests/large_file/test_large_file.py
index 87571fa..9afc615 100644
--- a/tests/large_file/test_large_file.py
+++ b/tests/large_file/test_large_file.py
@@ -24,6 +24,20 @@ def test_uninitialized() -> None:
         LargeFileS3("test-file")
 
 
+def test_bad_file_name() -> None:
+    with pytest.raises(ValueError):
+        LargeFileS3("../no-no", cache_only_mode=True)
+
+    with pytest.raises(ValueError):
+        LargeFileS3("is this wrong?", cache_only_mode=True)
+
+    with pytest.raises(FileNotFoundError):
+        LargeFileS3("!378378_fer-ef", cache_only_mode=True)  # this should work
+
+    with pytest.raises(FileNotFoundError):
+        LargeFileS3("3", cache_only_mode=True)  # this should work
+
+
 def test_bad_file_modes() -> None:
     with pytest.raises(ValueError):
         LargeFileS3("test-file", "w", version=3)