vba Excel data Validation error 'Application-defined or object-defined error'

I've read loads of similar questions and answers, but keep getting error. What I do is I export query via DoCmd.TransferSpreadsheet acExport, 8, "blabla", outputFile, True Then I'm attempting to add validation to a range in my new excel file. Here I get an error on setting AlertStyle:=xlValidAlertStop, Operator:=xlBetween, (no errors without them, but no validation is set as well, obviously) [Application-defined or object-defined error ] Running same code from Excel - cause no issues! Sub ApplyExcelFormating(ByVal myFile As String, ByVal mySpreadsheet As String) Dim myValidationList(1) As String myValidationList(0) = "YES" myValidationList(1) = "OK" Dim XL As Object, WB As Object, WKS As Object Set XL = CreateObject("Excel.Application") XL.Visible = True XL.DisplayAlerts = True Set WB = XL.Workbooks.Open(myFile) WB.Activate Set WKS = WB.worksheets(mySpreadsheet) Dim lastrow As Integer lastrow = WKS.UsedRange.Rows.Count WKS.Range("K2:K" & lastrow).Activate WKS.Range("K2:K" & lastrow).Select Only these two cause error: 'AlertStyle:=xlValidAlertStop, Operator:=xlBetween, With WKS.Range("K2:K" & lastrow).Validation .Delete .Add Type:=xlValidateList, AlertStyle:=xlValidAlertStop, Operator:=xlBetween, Formula1:=Join(myValidationList, ",") .IgnoreBlank = True .InCellDropdown = True .InputTitle = "" .ErrorTitle = "" .InputMessage = "" .ErrorMessage = "" .ShowInput = True .ShowError = True End With WB.Save XL.Workbooks.Close XL.Visible = True End Sub