'duplicate entry' warning

[davidav]

Greetings to all.

I need to return a "duplicate entry" message when one is entered in an ongoing column.(all of column b, each cell must be unique). The entries are alpha-numeric, like a driver's license serial number. Thanks in advance for the help. I am a baby excel user, but love to learn.

 

[ADAMC]

Hi there

Welcome to the board

Check this link:

http://www.cpearson.com/excel/NoDupEntry.aspx

Any problems post back

Edit**
Forgot to add you can add your own duplication message on the error alert tab.

 

[Barry Katcher]

Try the formula in C1 below, copied down

Book1
	A	B	C	D
1		Barry1
2		Elf2
3		3Geri
4		Barry1	dupe
5		Barry2
6		Elf3
7		Elf2	dupe
8		Geri3
Sheet1