Kodları aşağıdaki değiştirip, denermisiniz.?
Private Sub CommandButton1_Click()
On Error Resume Next
[e2:ee65000] = Empty
sut = Range("a1").End(xlToRight).Column
For a = 2 To Cells(65000, 1).End(xlUp).Row
For b = 5 To sut - 1
Set c = Sheets(Cells(a, 1).Text).Range("u2:u65000").Find(Cells(1, b))
If Not c Is Nothing Then
Cells(a, b) = Sheets(Cells(a, 1).Text).Cells(c.Row, 24)
End If
Next
If Application.Sum(Range("b" & a, Cells(a, sut))) <> 0 Then Cells(a, sut) = Application.Sum(Range("b" & a, Cells(a, sut)))
Next
Err = 0
End Sub