Unable to LOOP

This is what I have come up with so far.
But as soon as it opens the file stated in cell (1,2), it fails to go to (2,2)

Sub Macro1()
r = 1
sfiledir = Cells(1, 12)
sfile = Dir(sfiledir)

Do
    
    
    sfile = Dir(sfiledir & Cells(r, 2))
    'Defining sFile into a P file IF found
       
    If sfile <> "" Then Cells(r, 10) = "Y"
    'If sFile is not blank, or if found something, then register a YES
    
    
    Dim filepath As String
    filepath = "I:\" & sfile
    
    Workbooks.Open Filename:=filepath

    r = r + 1
    'go to next
  

Loop Until Cells(r, 2) = ""

End Sub