Das ist Dein Code (etwas modifiziert) - Wenn der CSV- Import früher funktioniert hat, dann auch jetzt.

Sub CSVimport()
'Makroname zum Impotieren von CSV-Dateien
     Dim pfad As Variant
     Dim DateinameKurz As Variant

     Dim Dateiname As Variant
     Dim WS As Worksheet
     pfad = FileSelection("*.csv")
     On Error GoTo weiter
     If pfad = False Then Exit Sub
weiter:
     For i = 1 To UBound(pfad)
          Dim TestArray() As String
          TestArray = Split(pfad(i), "\")
          Dateiname = TestArray(UBound(TestArray))
          DateinameKurz = Left(Dateiname, Len(Dateiname) - 4)
          ActiveWorkbook.Worksheets.Add
          With ActiveSheet.QueryTables.Add(Connection:="TEXT;" & pfad(i), Destination:=Range("A1"))
               .FieldNames = True
               .RowNumbers = False
               .FillAdjacentFormulas = False
               .PreserveFormatting = True
               .RefreshOnFileOpen = False
               .RefreshStyle = xlInsertDeleteCells
               .SavePassword = False
               .SaveData = True
               .AdjustColumnWidth = True
               .RefreshPeriod = 0
               .TextFilePromptOnRefresh = False
               .TextFilePlatform = 65001
               .TextFileStartRow = 1
               .TextFileParseType = xlDelimited
               .TextFileTextQualifier = xlTextQualifierDoubleQuote
               .TextFileConsecutiveDelimiter = False
               .TextFileTabDelimiter = False
               .TextFileSemicolonDelimiter = False
               .TextFileCommaDelimiter = True
               .TextFileSpaceDelimiter = False
               .TextFileColumnDataTypes = Array(1, 1)
               .TextFileTrailingMinusNumbers = True
               .Refresh BackgroundQuery:=False
          End With
          ActiveSheet.Name = DateinameKurz
     Next i
End Sub

Das in ein MODUL kopieren:

Function FileSelection(ByVal Endung As String) As Variant
     FileSelection = Application.GetOpenFilename(FileFilter:="Excel-Dateien (" + Endung + ")," + Endung, MultiSelect:=True)
End Function