Switching between workbooks,

From 1 workbook, I'm trying to open a 2nd workbook and then copy a value from this and paste it into the 1st. The code below is opening and selecting the right sheet but it doesn't copy the value from the 2nd workbook.

Any help would be greatly appreciated.

Dim PIWorkbook As Workbook
Dim PONumber1 As String
Dim PINumber1 As String

PINumber1 = Range("E3").Value

Set PIWorkbook = ActiveWorkbook

Workbooks.Open Filename:="N:\Workbook1.xlsx"
Application.Workbooks("Workbook1.xlsx").Activate

Sheets("PI").Select

Dim Numbers As Range

For Each Numbers In Range("J2:J10000")
    If Numbers = "" Then
        PONumber1 = Numbers.Offset(0, -1)
        Numbers.Value = PINumber1
        Exit For
    End If
Next

Windows("Workbook1.xlsx").Close savechanges:=True

PIWorkbook.Activate

Sheets("Sheet1").Select
Range("P3").Value = PONumber1

It looks like the code with only transfer the last value for PONumber1. Without the example workbook, its difficult to see what this might be - could it be a blank?

Go to advanced and there is a file upload mechanism available.

Is workbook1 locked for editing? Can you try opening it as readonly?