2 Problems with a VBA Macro and Date Formating - excel

Question

I have looked at other posts but cannot find anything that is similar enough to my problems. Any help will be appreciated.
I have a set of dates that come in everyday; the dates come in the following format: DD.MM.YYYY (I live in a country that has the day first). I need the data to change into DD/MM/YYYY. I then use these dates in a Vlookup as part of the data set that holds the information I wish to retrieve.
I need help with the following problems:
Problem # 1
When I use the macro and switch the "." with the "/", days 1 to 12 have been switched to the following format DD/MM/YYYY. However, the actual month and day have switched. Currently working in April so 01.04.2020 has been switched to 04/01/2020 (Reading as January fourth); 04/02/2020 (February second and so on....). How can I prevent this from happening so that everything stays in place and just the "." and the "/" change.
Problem #2
From day 13 and onwards the format looks right “13/04/2020”, however when I use it in the Vlookup, the formula will not bring any results back. In order for the Vlookup to work, I have to go to the cell that I just changed and press delete in front of the first digit, even though there is no space there; in order for the Vlookup to work.
Why does that happen? What can I do it so it work right after replacing the “.” and the “/”
Below is my code
Sub Dates()
Range(Range("G12"), Range("G12").End(xlDown)).Select
Selection.NumberFormat = "dd.mm.yyy"
Selection.Replace What:=".", Replacement:="/", LookAt:=xlPart, _
SearchOrder:=xlByRows, MatchCase:=False, SearchFormat:=False, _
ReplaceFormat:=False
Selection.NumberFormat = "dd/mm/yyy"
End Sub

Answer 1

Try,
Sub test()
Dim vDB, rngDB As Range
Dim s As Variant
Dim i As Long
Set rngDB = Range("G12", Range("G12").End(xlDown))
vDB = rngDB
For i = 1 To UBound(vDB, 1)
s = Split(vDB(i, 1), ".")
vDB(i, 1) = DateSerial(s(2), s(1), s(0))
Next i
rngDB = vDB
rngDB.NumberFormatLocal = "dd/mm/yyyy"
End Sub
Error Image
Correct Image

Answer 2

Here is a solution for your code as is.
I strongly recommend reading and further understanding How to avoid Select in Excel VBA to improve your code and reduce risk of runtime errors.
If you add this code to the bottom of your existing procedure (as it is shown in your question) it will loop through each cell and re-format it to the correct date value.
Dim myCell As Variant
Dim myRange As Range
Set myRange = Selection
For Each myCell In myRange
myCell.Value = Format(CDate(myCell), "DD/MM/YYYY")
Next
You might find this link helpful also:
Better way to find last used row
If you refine your code taking into account the information in both links, you will end up avoiding .Select and Selection. entirely, and your target range/cell will be less ambiguous.
I'd reformat it as follows:
Note: I have written this on Sheet1 of a new workbook, you would need to change the Sheets("...") reference to match your sheet name.
Sub dates()
Dim myRange As Range
Dim LastRow As Long
Dim myCell As Range
With ThisWorkbook.Sheets("Sheet1")
LastRow = .Cells(.Rows.Count, 7).End(xlUp).Row
Set myRange = Range("G12:G" & LastRow)
For Each myCell In myRange
myCell.Value = Replace(myCell, ".", "/")
myCell.Value = Format(CDate(myCell), "DD/MM/YYYY")
Next myCell
End With
End Sub
Now it's a lot clearer where on our workbook we are making changes which helps improve readability for yourself and others (such as other users on SO) along with reduces ambiguity and risk of RunTime errors.

Answer 3

Thanks for the text to column advise this is what I did for it to work:
Sub Dates ()
Dim rg As Range
Set rg = Range("G12").CurrentRegion
rg.TextToColumns Destination:=Range("H2"), ConsecutiveDelimiter:=True, DataType:=xlDelimited, Other:=True, OtherChar:="."
lr = ActiveSheet.Cells(Rows.Count, "G").End(xlUp).Row
Range("K2").Formula = "=DATE(J2,I2,H2)"
Range("K2").AutoFill Range("K2:K" & lr)