diff --git a/erpnext/manufacturing/doctype/workstation/workstation.json b/erpnext/manufacturing/doctype/workstation/workstation.json
index 56e1b4c..9f72e5c 100644
--- a/erpnext/manufacturing/doctype/workstation/workstation.json
+++ b/erpnext/manufacturing/doctype/workstation/workstation.json
@@ -412,7 +412,7 @@
    "read_only": 0, 
    "remember_last_selected_value": 0, 
    "report_hide": 0, 
-   "reqd": 1, 
+   "reqd": 0, 
    "search_index": 0, 
    "set_only_once": 0, 
    "unique": 0
@@ -429,7 +429,7 @@
  "issingle": 0, 
  "istable": 0, 
  "max_attachments": 0, 
- "modified": "2016-12-13 04:52:59.657226", 
+ "modified": "2016-12-13 05:04:54.668633", 
  "modified_by": "Administrator", 
  "module": "Manufacturing", 
  "name": "Workstation", 
diff --git a/erpnext/manufacturing/doctype/workstation/workstation.py b/erpnext/manufacturing/doctype/workstation/workstation.py
index 5095784..dd1c9f2 100644
--- a/erpnext/manufacturing/doctype/workstation/workstation.py
+++ b/erpnext/manufacturing/doctype/workstation/workstation.py
@@ -58,6 +58,9 @@
 def is_within_operating_hours(workstation, operation, from_datetime, to_datetime):
 	operation_length = time_diff_in_seconds(to_datetime, from_datetime)
 	workstation = frappe.get_doc("Workstation", workstation)
+	
+	if not workstation.working_hours:
+		return
 
 	for working_hour in workstation.working_hours:
 		if working_hour.start_time and working_hour.end_time:
diff --git a/erpnext/manufacturing/doctype/workstation_working_hour/workstation_working_hour.json b/erpnext/manufacturing/doctype/workstation_working_hour/workstation_working_hour.json
index b9cd174..89ca714 100644
--- a/erpnext/manufacturing/doctype/workstation_working_hour/workstation_working_hour.json
+++ b/erpnext/manufacturing/doctype/workstation_working_hour/workstation_working_hour.json
@@ -9,11 +9,13 @@
  "doctype": "DocType", 
  "document_type": "", 
  "editable_grid": 1, 
+ "engine": "InnoDB", 
  "fields": [
   {
    "allow_on_submit": 0, 
    "bold": 0, 
    "collapsible": 0, 
+   "columns": 0, 
    "fieldname": "start_time", 
    "fieldtype": "Time", 
    "hidden": 0, 
@@ -21,6 +23,7 @@
    "ignore_xss_filter": 0, 
    "in_filter": 0, 
    "in_list_view": 1, 
+   "in_standard_filter": 0, 
    "label": "Start Time", 
    "length": 0, 
    "no_copy": 0, 
@@ -29,6 +32,7 @@
    "print_hide": 0, 
    "print_hide_if_no_value": 0, 
    "read_only": 0, 
+   "remember_last_selected_value": 0, 
    "report_hide": 0, 
    "reqd": 1, 
    "search_index": 0, 
@@ -39,6 +43,7 @@
    "allow_on_submit": 0, 
    "bold": 0, 
    "collapsible": 0, 
+   "columns": 0, 
    "fieldname": "column_break_2", 
    "fieldtype": "Column Break", 
    "hidden": 0, 
@@ -46,6 +51,7 @@
    "ignore_xss_filter": 0, 
    "in_filter": 0, 
    "in_list_view": 0, 
+   "in_standard_filter": 0, 
    "length": 0, 
    "no_copy": 0, 
    "permlevel": 0, 
@@ -53,6 +59,7 @@
    "print_hide": 0, 
    "print_hide_if_no_value": 0, 
    "read_only": 0, 
+   "remember_last_selected_value": 0, 
    "report_hide": 0, 
    "reqd": 0, 
    "search_index": 0, 
@@ -63,6 +70,7 @@
    "allow_on_submit": 0, 
    "bold": 0, 
    "collapsible": 0, 
+   "columns": 0, 
    "fieldname": "end_time", 
    "fieldtype": "Time", 
    "hidden": 0, 
@@ -70,6 +78,7 @@
    "ignore_xss_filter": 0, 
    "in_filter": 0, 
    "in_list_view": 1, 
+   "in_standard_filter": 0, 
    "label": "End Time", 
    "length": 0, 
    "no_copy": 0, 
@@ -78,6 +87,7 @@
    "print_hide": 0, 
    "print_hide_if_no_value": 0, 
    "read_only": 0, 
+   "remember_last_selected_value": 0, 
    "report_hide": 0, 
    "reqd": 1, 
    "search_index": 0, 
@@ -88,30 +98,7 @@
    "allow_on_submit": 0, 
    "bold": 0, 
    "collapsible": 0, 
-   "fieldname": "section_break_2", 
-   "fieldtype": "Column Break", 
-   "hidden": 0, 
-   "ignore_user_permissions": 0, 
-   "ignore_xss_filter": 0, 
-   "in_filter": 0, 
-   "in_list_view": 0, 
-   "length": 0, 
-   "no_copy": 0, 
-   "permlevel": 0, 
-   "precision": "", 
-   "print_hide": 0, 
-   "print_hide_if_no_value": 0, 
-   "read_only": 0, 
-   "report_hide": 0, 
-   "reqd": 0, 
-   "search_index": 0, 
-   "set_only_once": 0, 
-   "unique": 0
-  }, 
-  {
-   "allow_on_submit": 0, 
-   "bold": 0, 
-   "collapsible": 0, 
+   "columns": 0, 
    "default": "1", 
    "fieldname": "enabled", 
    "fieldtype": "Check", 
@@ -120,6 +107,7 @@
    "ignore_xss_filter": 0, 
    "in_filter": 0, 
    "in_list_view": 1, 
+   "in_standard_filter": 0, 
    "label": "Enabled", 
    "length": 0, 
    "no_copy": 0, 
@@ -128,6 +116,7 @@
    "print_hide": 0, 
    "print_hide_if_no_value": 0, 
    "read_only": 0, 
+   "remember_last_selected_value": 0, 
    "report_hide": 0, 
    "reqd": 0, 
    "search_index": 0, 
@@ -145,7 +134,7 @@
  "issingle": 0, 
  "istable": 1, 
  "max_attachments": 0, 
- "modified": "2016-07-11 03:28:10.225704", 
+ "modified": "2016-12-13 05:02:36.754145", 
  "modified_by": "Administrator", 
  "module": "Manufacturing", 
  "name": "Workstation Working Hour",