Hi Niyas, Thank you for replying ... Yup, I did some customizations on SO line but I can create an invoiceable line, only partial invoice had this problem. 

Hi,

As far as my understanding, I think you have done some customizations in the db, thats why this error. The error says that there is a mandatory field , but you are not supplied the value into it. The field is shown in the error message, categ_id.

Thanks