I used this code on the worksheet (found it on this site, I think)

Private Sub Worksheet_Change(ByVal Target As Range)
If Not Intersect(Me.[o2], Target) Is Nothing Then
On Error GoTo InvalidName
Me.Name = Target.Value
Exit Sub
End If
InvalidName:
MsgBox "Invalid sheet name."
End Sub


which worked great when I did it, renaming the sheet to the content of O2.
I've just opened it today, and although valid names work, and invalid names
call the error message, any change to any other cell also calls the error
message. What's going on?

thanks,
Andy