Как заметил @FunThomas - вы используете неправильный синтаксис в операторе Select Case.Вы также не добавляете расширение файла к имени файла.В настоящее время вы ищете файл с именем "k111", а не "k111.xlsx".
Этот код должен работать:
Sub datapull_manual()
Dim FilePerUser As String
Dim User As Variant
User = Worksheets("prp").Range("v2")
Dim FileDir As String
FileDir = "\\network\test folder\destination\"
'user names to automatically open file as per every user
'Change Case to look at 'User' variable.
'Case "Mo", not 'Case User = "Mo"'
Select Case User
Case "Mo"
FilePerUser = "K111.xlsx"
Case "To"
FilePerUser = "k222.xlsx"
Case "Vo"
FilePerUser = "k333.xlsx"
End Select
Workbooks.Open Filename:=(FileDir & FilePerUser)
Columns("A:S").Copy
Windows("Test.xlsb").Activate
Sheets("test123").Select
Cells.Select
Range("A2").Activate
ActiveSheet.Paste
End Sub
Нижняя часть вашего кода может быть улучшена путем ссылки на рабочие книги с переменными:
Sub datapull_manual()
Dim FilePerUser As String
Dim User As Variant
Dim WB As Workbook
Dim WB1 As Workbook
User = Worksheets("prp").Range("v2")
Dim FileDir As String
FileDir = "\\network\test folder\destination\"
'user names to automatically open file as per every user
'Change Case to look at 'User' variable.
'Case "Mo", not 'Case User = "Mo"'
Select Case User
Case "Mo"
FilePerUser = "k111.xlsx"
Case "To"
FilePerUser = "k222.xlsx"
Case "Vo"
FilePerUser = "k333.xslx"
End Select
'Open & set reference to the workbook.
Set WB = Workbooks.Open(Filename:=FileDir & FilePerUser)
Set WB1 = Workbooks("Test.xlsb") 'Set reference to Test workbook.
'Set WB1 = ThisWorkbook 'If Test.xlsb is the workbook containing this code.
'Use references to copy data - no need to activate or select anything.
WB.Worksheets("Sheet1").Columns("A:S").Copy _
Destination:=WB1.Worksheets("Test123").Range("A2")
End Sub