Your help got me to this, which works just fine!
Thanks Jim!
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Sub OpenAllWorkbooks2()    'open all workbooks in a folder location
   Dim oFSO As Object
   Dim vFileCount As Variant
   Dim sCount As String
   Dim Folder As Object
   Dim Files As Object
   Dim file As Object
   Dim sFileName As String

   Application.ScreenUpdating = False
   Set oFSO = CreateObject("Scripting.FileSystemObject")
   vFileCount = oFSO.GetFolder("M:\Qadocs\IPI'S\Test Folder\Run").Files.Count
   Set Folder = oFSO.GetFolder("M:\Qadocs\IPI'S\Test Folder\Run")    'set
folder location here
   sCount = vFileCount - 1
   vFileCount = vFileCount - 1
   'MsgBox sCount
   For Each file In Folder.Files
       sFileName = file
       If Right(sFileName, 3) = "xls" Or _
          Right(sFileName, 3) = "XLS" Or _
          Right(sFileName, 4) = "xlsx" Then
           'Workbooks.Open FileName:=file.Path
           'code below is for passing workbook password on open event,
requires to arguments
           Workbooks.Open FileName:=file.Path, Password:="2000",
WriteResPassword:="2000"    'pass workbook.open password
           '<<<<< run macro here on Activeworkbook
           Dim wkSheet As Worksheet
           Dim i
           For i = 4 To Worksheets.Count    'Ignore first three sheets
               Application.DisplayAlerts = False
                   Sheets(i).Activate    'start with first IPI data sheet
                   ActiveSheet.Unprotect "2000"
                   Range("D4").Select
                   Selection.NumberFormat = "General"
                   ActiveCell.Formula =
"=MID(D6,4,FIND(""-"",D6)-4)&IF(RIGHT(D6)<>""1)"","" CONT"","""")"
                   Range("B6").Select
                   ActiveCell.FormulaR1C1 = "SHT"
                   Range("D6").Select
                   Selection.NumberFormat = "General"
                   ActiveCell.FormulaR1C1 = _
                   
"=MID(CELL(""filename"",R[-5]C[-3]),SEARCH(""]"",CELL(""filename"",R[-5]C[-3]))+1,1024)"
                   Range("D10").Select
                   ActiveSheet.Protect "2000"
                   Sheets("Master Sheet").Select
                   Application.StatusBar = vFileCount & " of " & sCount
               Next i
               vFileCount = vFileCount - 1
               Application.DisplayAlerts = True
           Application.DisplayAlerts = True
           ActiveWorkbook.Close SaveChanges:=True
       End If
   Next file
   Set oFSO = Nothing
   Application.ScreenUpdating = True
   Application.StatusBar = ""
End Sub
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