How do I know which sheet the loop refers to / is valid for? According to my
logic it should be previous sheet, but it seems it is the other sheet (start
here)? Not logical as I select the previous sheet just before the loop starts.

Sheets("start here!").Activate
ActiveSheet.Previous.Select

x = 2

Do While Cells(x, 2).Value < ""

Cells(x, 9) = Application.VLookup(Cells(x, 8),
Worksheets("Prognos").Range("A1:B50000"), 2, False)

x = x + 1

Loop

End Sub