Option Explicit
Sub TheSpaceExtractorWithAlert()
Dim Plage As Range, Cell As Range
Dim Container As Variant
Dim StringComplet As String
Dim Alert As String
Dim i As Byte
Set Plage = Range('C1:C' & Range('C65536').End(xlUp).Row)
For Each Cell In Plage
StringComplet = Cell
Container = Split(StringComplet, ' ')
If UBound(Container) > 0 Then
For i = 0 To UBound(Container)
Cell.Offset(0, i + 1) = Container(i)
Next i
Else
Alert = Alert & Cell.Address(0, 0) & vbTab & StringComplet & vbCrLf & vbTab
Cell.Interior.ColorIndex = 3
End If
Next Cell
If Len(Alert) > 0 Then
MsgBox 'Les Cellules suivantes n'ont pas pu être traïtées' & vbCrLf & vbTab & Alert, vbCritical
End If
End Sub