'-----Workbook A-----'
Option Explicit

Private Sub Workbook_Open()

Application.Visible = False
ThisWorkbook.Activate
Dim wb As Workbook

For Each wb In Workbooks
    If wb.Name = "WorkbookB.xlsm" Then
        wb.Close xlDoNotSaveChanges
    End If
Next wb

Call UserForm1.Show

End Sub

'-----Userform1-----'
Option Explicit

Private Sub CommandButton1_Click()
    Application.Visible = True
    UserForm1.Hide
End Sub

Private Sub CommandButton2_Click()
    TextBox1.Value = Sheets("SheetA").Range("A1")
End Sub

Private Sub UserForm_Initialize()

    Application.Visible = False

End Sub