Thanks, It may have helped. I do have an error, that I do not know how to resolve. Here is what I have written and the error [image: Error] Error: Compile Error: Expecting '}' but was: '' at line 21 column 1 [image: image.png] trigger SerialNumber on Case (after insert, after update) { List SerialList = new List(); for (Case a:Trigger.new) { SerialList.add(a.Serial_number_Full_list__c); } List SerialNum = [Select Name from custom_serial_number__c where Name in :SerialList]; if (SerialNum.size() > 0 ){ for (Integer i = 0; i < Trigger.new.size(); i++) { if (Trigger.new[i].Serial_number_Full_list__c != null) { Trigger.new[i].custom_serial_number__c = SerialNum[i].ID; } else { Trigger.new[i].custom_serial_number__c = null; } Kind regards, Jason Harris Viessmann Manufacturing Company Inc. 750 McMurray Road Waterloo, ON N2V 2G5 To serve you better please call us on the toll-free “Viessmann TechInfo Line” for all calls relating to Viessmann Heating Products. Or refer to the “Pro Login” section of our website for detailed Product Literature & Parts Catalog. TechInfo Line: 888-484-8643 Fax: 519-772-1023 Email: HJa@viessmann.com Website: www.viessmann.ca Pro Login: http://www.viessmann.ca/en/service/Login.html