Hi,

You can use Data, Validation to prevent the entry of duplicates:

You can prevent duplicate entries in a range as follows:

1. Highlight the range, lets say A1:A100
2. Choose the command Data, Validation
3. Under Allow choose Custom
4. Enter the following formula in the Formulas box:
=COUNTIF(A$1:A$100,A1)=1

One thing to keep in mind - if the user copies and pastes data into the
range where the Data Validation is, it is wiped out and anything can be
entered.

If this is helpful, please click the Yes button.

Cheers,
Shane Devenshire
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"HR Director" wrote:

I have a cloumn that you have to put in an EE number, it the useis Vkookup
to find the employee and the propigates the information requested. I need a
way to tell if I enter a duplicate number in the EE number column. any ideas