NameSpace.Logon method (Outlook)

Logs the user on to MAPI, obtaining a MAPI session.

Syntax

expression. Logon( _Profile_ , _Password_ , _ShowDialog_ , _NewSession_ )

expression A variable that represents a NameSpace object.

Parameters

Name	Required/Optional	Data type	Description
Profile	Optional	Variant	The MAPI profile name, as a String, to use for the session. Specify an empty string to use the default profile for the current session.
Password	Optional	Variant	The password (if any), as a String, associated with the profile. This parameter exists only for backwards compatibility and for security reasons, it is not recommended for use. Microsoft Outlook will prompt the user to specify a password in most system configurations. This is your logon password and should not be confused with PST passwords.
ShowDialog	Optional	Variant	True to display the MAPI logon dialog box to allow the user to select a MAPI profile.
NewSession	Optional	Variant	True to create a new Microsoft Outlook session. Since multiple sessions cannot be created in Outlook, this parameter should be specified as True only if a session does not already exist.

Remarks

Use the Logon method only to log on to a specific profile when Outlook is not already running. This is because only one Outlook process can run at a time, and that Outlook process uses only one profile and supports only one MAPI session. When users start Outlook a second time, that instance of Outlook runs within the same Outlook process, does not create a new process, and uses the same profile.

If Outlook is already running, using this method does not create a new Outlook session or change the current profile to a different one.

If Outlook is not running and you only want to start Outlook with the default profile, don't use the Logon method. A better alternative is shown in the following code example, InitializeMAPI: first, instantiate the Outlook Application object, then reference a default folder such as the Inbox. This has the side effect of initializing MAPI to use the default profile and to make the object model fully functional.

Sub InitializeMAPI ()

    ' Start Outlook.
    Dim olApp As Outlook.Application
    Set olApp = CreateObject("Outlook.Application")
    
    ' Get a session object. 
    Dim olNs As Outlook.NameSpace
    Set olNs = olApp.GetNamespace("MAPI")
    
    ' Create an instance of the Inbox folder. 
    ' If Outlook is not already running, this has the side
    ' effect of initializing MAPI.
    Dim mailFolder As Outlook.Folder
    Set mailFolder = olNs.GetDefaultFolder(olFolderInbox)

    ' Continue to use the object model to automate Outlook.
End Sub

Starting in Outlook 2010, if you have multiple profiles, you have configured Outlook to always use a default profile, and you use the Logon method to log on to the default profile without prompting the user, the user will receive a prompt to choose a profile anyway. To avoid this behavior, don't use the Logon method; use the workaround suggested in the preceding InitializeMAPI example instead.

Example

This Visual Basic for Applications example uses the Logon method to log on to a new session, displaying the dialog box to verify the profile name and enter password.

Sub StartOutlook() 
    Dim myNameSpace As Outlook.NameSpace 
  
    Set myNameSpace = Application.GetNamespace("MAPI") 
    myNameSpace.Logon "LatestProfile", , True, True 
End Sub

See also

NameSpace Object

How to: Obtain and Log On to an Instance of Outlook

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