Have you tried it as below, keep in mind you need to specify the name of the shared mailbox in the below code:
Dim mynamespace As outlook.Namespace
Dim strRowData As String
Dim strDelimiter As String
Dim myDestFolder As outlook.Folder
Dim ShareInbox As outlook.MAPIFolder
Dim SubFolder As Object
Dim InputFolder As String
Dim OutputFolder As String
Dim ProdMail As String
Dim SavePath As String
Dim oXLApp As Object, oXLwb As Object, oXLws As Object
Dim lRow As Long
On Error Resume Next
Set oXLApp = GetObject(, "Excel.Application")
'~~> If not found then create new instance
If Err.Number <> 0 Then
Set oXLApp = CreateObject("Excel.Application")
End If
Err.Clear
On Error GoTo 0
'~~> Open the relevant file
SavePath = "\\C:\Macro"
Set oXLwb = oXLApp.Workbooks.Open(SavePath & "\Test.xlsx")
'Extract Mailbox and subfolder details from a sheet named as "Folder Details"
Set oXLws = oXLwb.Sheets("Folder Details")
ProdMail = oXLws.Range("B1")
InputFolder = oXLws.Range("B2")
OutputFolder = oXLws.Range("B3")
strRowData = ""
' Code to extract emails from specific subfolder within shared folder and copy the data across excel spreadsheet.
Set mynamespace = outlook.GetNamespace("MAPI")
Set ShareInbox = mynamespace.Session.Folders.Item("Name of shared mailbox") ' change to suit
Set SubFolder = ShareInbox.Folders.Item(InputFolder) 'Change this line to specify folder
Set myDestFolder = ShareInbox.Folders.Item(OutputFolder)
When I tested the above code the folders that I located were in a shared mailbox but outside of the shared mailbox inbox so to speak.