How to stop duplication in data validation list

[Zubair]

Mr. Excel.xlsx
	A	B	C	D	E	F
1	Entry Form				Data Base
2	Brand	Size			Brand	Size
3	Alpha Kraft	20			Alpha Kraft	20
4	Alpha Kraft	24			Box Board	22
5	Ultra Fluting	26			Delta	24
6	Ultra Fluting	32			Dubai	26
7	Delta	20			Fluting	28
8	Liner	26			Liner	30
9	Special	46			Nazeer Dubai	32
10					Nazeer Kraft	34
11					Nazeer Kraft 160	36
12					Special	38
13					Ultra Fluting	40
14						42
15						44
16						46
17						48
18						50
19
20
21
Sheet2

Cells with Data Validation
Cell	Allow	Criteria
A3:A18	List	=$E$3:$E$13

Hi,

A3:A9 is from E3:E13 and B3:B9 is from F3:F18 through data validation list.

No duplicate combination of Brand & Size is acceptable.

So formula required in data validation in column B that for example when user select Brand "Alpha Kraft" in A3 & A4 and size 20 in B3 and B4 it should stop doing this in B4.

Similarly for all Brands by size duplication.

 

[etaf]

glad it is working ok

extremely sorry for the inconvenience

No problem

I thought after re-reading , that you only wanted numbers that appeared in column F and not allow any other numbers or duplicated
Which i had not been able to solve
So pleased its all sorted now , as i'm away for a few days now