Thanks Cosmos,

You helped a lot. I had to modify what you gave me but it did end up doing what I needed. Rather than using before hand, I used Enter and made the following changes and it works great.

[vba]Private Sub C1_Enter()

If Me.C1 > 500 Then
MsgBox "Do Not Enter Over 500 Sheets", vbCritical, "Please re-enter."
Me.C1.SetFocus
End If

End Sub[/vba]

I also did set the validation as you suggest to <=500.

Thanks again.

Gary