Hei Aksel
do not use lincedcell in your combobox (= empty)
and try this.

I use range(e2) to put the selections address

Private Sub ComboBox1_Change()
Dim b As String
With ComboBox1
b = Range(.ListFillRange)(.ListIndex + 1).Address(False, False)
ActiveSheet.Range("E2") = b
End With





'
End Sub

Private Sub CommandButton1_Click()
Dim b As String
b = ActiveSheet.Range("e2").Value
Range(b).Offset(0, 1) = ActiveSheet.Range("D2").Value
End Sub


Regards

Yngve Ha en god dag.