diff --git a/base/univention-system-setup/umc/python/setup/__init__.py b/base/univention-system-setup/umc/python/setup/__init__.py
index bf9ca8d..7b5d7ca 100644
--- a/base/univention-system-setup/umc/python/setup/__init__.py
+++ b/base/univention-system-setup/umc/python/setup/__init__.py
@@ -391,7 +391,7 @@ def _append(key, message):
 		# host and domain name
 		packages = set(values.get('components', []))
 		_check('hostname', util.is_hostname, _('The hostname or the hostname part of the fully qualified domain name is invalid. Please go back to the host setting and make sure, that the hostname only contains letter (a-zA-Z) and digits (0-9).'))
-		_check('hostname', lambda x: len(x) <= 13, _('A valid NetBIOS name can not be longer than 13 characters. If Samba is installed, the hostname should be shortened.'), critical=('univention-samba' in packages or 'univention-samba4' in packages))
+		_check('hostname', lambda x: len(x) <= 13, _('A valid NetBIOS name can not be longer than 13 characters. If Samba is installed, the hostname should be shortened.'), critical=(ad_member or 'univention-samba' in packages or 'univention-samba4' in packages))
 		_check('domainname', util.is_domainname, _("Please enter a valid fully qualified domain name (e.g. host.example.com)."))
 		hostname = allValues.get('hostname', '')
 		domainname = allValues.get('domainname', '')