Hi,
Thank you.

For column 'N' the formula is not working as per requirement. It's taking any letter before a receipt no. I want to take a capital letter 'D' before a duplicate number only and not any other letter. If I enter a duplicate receipt no. then I want to have a letter 'D' before a receipt no. automatically.

For column 'P' it's not allowing any value if there is a duplicate receipt no. preceded by a letter 'D'. If there is a duplicated receipt number in column 'N' then I want a 0 value only in column 'P'.

If it's not possible by dv formula then I will like to use a vba solution for it.

Thank you.