Here are a couple of routines that I use that you can play about with, they
should be clear

private Sub TextBox2_KeyPress(ByVal KeyAscii As _
MSForms.ReturnInteger)
Dim cDelim As Long
   cDelim = Len(TextBox2.Text) - Len(Replace
(TextBox2.Text, "/", ""))
   Select Case KeyAscii
       Case Asc("0") To Asc("9"): 'OK
       Case Asc("/"):
           If cDelim = 2 Then
               KeyAscii = 0
           Else
               cDelim = cDelim + 1
           End If
       Case Else: KeyAscii = 0
   End Select
End Sub

Private Sub TextBox1_KeyPress(ByVal KeyAscii As MSForms.ReturnInteger)
   Select Case KeyAscii
       Case 45         'negative
           If Len(Trim(TextBox1.Text)) > 1 Then
               Beep
               KeyAscii = 0
           End If
       Case 46         'period
           If InStr(TextBox1.Text, ".") > 0 Then
               Beep
               KeyAscii = 0
           End If
       Case 48 To 57 'numbers
           If InStr(TextBox1.Text, ".") > 0 Then
               If Len(TextBox1.Text) > InStr(TextBox1.Text, ".") + 1 Then
                   Beep
                   KeyAscii = 0
               End If
           End If
       Case Else 'Discard anything else
           Beep
           KeyAscii = 0
   End Select
End Sub

Have a look at the keypress event for that textbox.

Maybe this will do it

Private Sub TextBox1_Exit(ByVal Cancel As MSForms.ReturnBoolean)
Dim B
B = TextBox1.Value
 If B <> Format(TextBox1.Value, "mm/dd/yy") Then
 Cancel = True And MsgBox("Format Must Be mm/dd/yy", vbCritical)
 End If
End Sub

You can use the code at the bottom of my posting to do what you asked (it
will also stop the user from pasting in text containing characters other
than digits and the slash character). You will still have to validate the
entry after the user has finished typing his/her entry to make sure it is a
valid date (you can use the IsDate function for this).

Just out of curiosity, have you considered using one of the drop-down
calendar controls to take your date input (the input mechanism is much more
natural for the user and it foolproof date-entry-wise)? I use the "Microsoft
Date and Time Picker Control" for this purpose. You can add it to your
UserForm's Toolbox by right-clicking the Toolbox and clicking on "Additional
Controls", then put a checkmark next to the "Microsoft Date and Time Picker
Control" item and click OK. Try it... I think you will like it.

Rick

'***********BEGIN PASTE***********
Dim LastPosition As Long

Private Sub TextBox1_Change()
 Static LastText As String
 Static SecondTime As Boolean
 With TextBox1
   If Not SecondTime Then
     If .Text Like "*[!0-9/]*" Then
       Beep
       SecondTime = True
       .Text = LastText
       .SelStart = LastPosition
     Else
       LastText = .Text
     End If
   End If
 End With
 SecondTime = False
End Sub

Private Sub TextBox1_KeyPress(ByVal KeyAscii As MSForms.ReturnInteger)
 LastPosition = TextBox1.SelStart
End Sub
'***********END PASTE***********