diff --git a/frappe/core/doctype/custom_field/custom_field.py b/frappe/core/doctype/custom_field/custom_field.py
index 852786f914..a0e27b5953 100644
--- a/frappe/core/doctype/custom_field/custom_field.py
+++ b/frappe/core/doctype/custom_field/custom_field.py
@@ -3,7 +3,7 @@
 
 from __future__ import unicode_literals
 import frappe
-from frappe.utils import cint, cstr
+from frappe.utils import cstr
 from frappe import _
 
 from frappe.model.document import Document
@@ -30,12 +30,12 @@ class CustomField(Document):
 			frappe.throw(_("Fieldname not set for Custom Field"))
 
 	def on_update(self):
-		# validate field
-		from frappe.core.doctype.doctype.doctype import validate_fields_for_doctype
-
 		frappe.clear_cache(doctype=self.dt)
 
-		validate_fields_for_doctype(self.dt)
+		if not self.ignore_validate:
+			# validate field
+			from frappe.core.doctype.doctype.doctype import validate_fields_for_doctype
+			validate_fields_for_doctype(self.dt)
 
 		# create property setter to emulate insert after
 		self.create_property_setter()
diff --git a/frappe/core/doctype/customize_form/customize_form.py b/frappe/core/doctype/customize_form/customize_form.py
index e65023400e..0f92b0c996 100644
--- a/frappe/core/doctype/customize_form/customize_form.py
+++ b/frappe/core/doctype/customize_form/customize_form.py
@@ -167,6 +167,7 @@ class CustomizeForm(Document):
 				changed = True
 
 		if changed:
+			custom_field.ignore_validate = True
 			custom_field.save()
 
 	def delete_custom_fields(self):