... From XML File

If you want to load ribbon from a Ribbon XML file follow these instructions:

In a standard module create the function "LoadRibbons":

Public Function LoadRibbons()
'Load ribbons from XML file into the database
On Error GoTo Error1
Dim f As Long
Dim strText As String
Dim strOut As String
f = FreeFile
    Open "C:\Folder\Ribbon\AccRibbon.xml" For Input As f
    ' C:\Folder\... has to be replaced by your folder/filename.
    Do While Not EOF(f)
        Line Input #f, strText
        strOut = strOut & strText
    Loop
    Application.LoadCustomUI "AppRibbon_1", strOut
Error1_Exit:
    On Error Resume Next
    Close f
    Exit Function
Error1:
    Select Case Err
        Case 32609
        ' Ribbon already loaded
    Case Else
        MsgBox "Error: " & Err.Number & vbCrLf & _
               Err.description, vbCritical, _
               "Error", Err.HelpFile, Err.HelpContext
    End Select
Resume Error1_Exit
End Function

Create a macro named "AutoExec" which will be run when you open the database:

Re-start the database.

Select a ribbon for this database:

"Office Button" / Button "Access-Options" / "Current Database" / "Ribbon and Toolbar Options" / "Ribbon Name:" Select the ribbon that should be loaded when you open the database.

After another re-start of the database your ribbon will be displayed.