Попробуйте это.
Sub DeleteDuplicatesOnSheets()
Dim Ws As Worksheet
Dim Cl As Range
Dim ValU As String
Dim Qty As Long
Dim Rng As Range
For Each Ws In Worksheets
On Error Resume Next
With CreateObject("scripting.dictionary")
For Each Cl In Ws.Range("C2", Ws.Range("C" & Rows.Count).End(xlUp))
ValU = Join(Application.Transpose(Application.Transpose(Cl.Resize(, 4))))
If Not .exists(ValU) Then
.Add ValU, Nothing
Else
Qty = Qty + 1
If Rng Is Nothing Then
Set Rng = Cl
Else
Set Rng = Union(Rng, Cl)
End If
End If
Next Cl
If Not Rng Is Nothing Then Rng.EntireRow.Delete
.RemoveAll
End With
Next Ws
MsgBox Qty & " rows have been deleted"
End Sub