diff --git a/src/gam/__init__.py b/src/gam/__init__.py
index 7be99de6..ce0ffb7b 100755
--- a/src/gam/__init__.py
+++ b/src/gam/__init__.py
@@ -3538,7 +3538,11 @@ def getDriveFileAttribute(i, body, parameters, myarg, update=False):
                 sys.argv[i+2], f'gam <users> {operation} drivefile')
             i += 3
             if len(sys.argv) > i and sys.argv[i].lower() == 'reason':
-                body['contentRestrictions'][0]['reason'] = sys.argv[i+1]
+                if body['contentRestrictions'][0]['readOnly']:
+                    body['contentRestrictions'][0]['reason'] = sys.argv[i+1]
+                else:
+                    controlflow.invalid_argument_exit(
+                        'reason', 'contentrestrictions readonly false')
                 i += 2
         else:
             controlflow.invalid_argument_exit(
diff --git a/src/gam/var.py b/src/gam/var.py
index f91affc9..6624c267 100644
--- a/src/gam/var.py
+++ b/src/gam/var.py
@@ -380,6 +380,7 @@ DRIVEFILE_FIELDS_CHOICES_MAP = {
     'appdatacontents': 'appDataContents',
     'cancomment': 'canComment',
     'canreadrevisions': 'canReadRevisions',
+    'contentrestrictions': 'contentRestrictions',
     'copyable': 'copyable',
     'copyrequireswriterpermission': 'copyRequiresWriterPermission',
     'createddate': 'createdDate',