A tutorial for Outlook 2010, Outlook 2013, and Outlook 2016 is at Tutorial: Set up Outlook.com account to sync Calendar and Contacts

Use this method with Outlook 2010 and above with Outlook.com accounts to sync your calendar and contacts with other computers or smartphones "over the air" when your personal email account is POP3 or IMAP. (Outlook 2007 will sync Outlook.com and Office 365 Exchange accounts, however, Outlook 2007 will suffer from degraded service.)

All you need is a Microsoft Account. If you have a Microsoft account for your personal address (gmail.com, comcast.net, etc), you will need to add an Outlook.com alias to the account before you can add it to Outlook. If the alias is not set as the default address for the account, it will be added to Outlook using an Outlook_big-long-code@ format for the address). Set the outlook.com address as Primary to fix this.

Using an Outlook.com account for email too? See Configuring an Outlook.com account in Outlook.

You do not need to configure Outlook.com to pull in your other email accounts to use it for Calendar and Contacts. In fact, I do not recommend adding your email account as a connected account to outlook.com because, at this time, you cannot send mail from the connected accounts using Outlook desktop without sending it 'from outlook.com on behalf of other address'.

You'll need to move or copy existing appointments and contacts to the new Outlook.com data file. You can move the appointments and contacts between folders within Outlook using drag and drop or the Move to folder command. For the Calendar, use the List view, select all (Ctrl+A) then drag or use Move to folder command.

You should set the Outlook.com Account as your default data file (this puts the calendar on the To-Do Bar) but I do not recommend setting it as the default email account, unless you are using it for email too.

If you enabled two-factor authentication on the Outlook.com account, you'll need to generate an app password to use with the account in Outlook. Log into Outlook.com and check your account options for instructions.

Setup Account using Outlook.com

Step 1: Create a Microsoft Account if you don't have one already. If you are using a non-Microsoft domain (like Comcast.com, gmail.com, or your own domain name) for your Microsoft Account, you'll need to add an outlook.com alias to your Outlook.com account before you can set it up in Outlook.

Step 2: Add the account to Outlook using the Add Account wizard. Go to File, Add Account and enter your Outlook.com email address. Enter your password when asked.

Once the Outlook.com account is added to Outlook, you'll have two accounts in Outlook: your ISP or "real" email and the Outlook.com account for calendar, tasks, and contacts.

When you send mail, Outlook 2010, 2013, and 2016 will use the account associated with the folders you are looking at. This means if you are viewing the calendar in Outlook.com data file and start a new message, Outlook will use the Outlook.com account to send the message. However, you can set an option or a registry value to always use the default email account for new messages.

This option was added to Outlook 2016's Mail settings. In File, Options, Mail, look in the Send messages section about two-thirds down for Always use the default account when composing new messages.

Set your email account to be the default on the Email tab.

Set the Outlook.com account to be the default data file on the Data Files tab. This puts the calendar in the To-Do bar and new appointments and contacts will go into it's Calendar and Contacts folder.

The final piece of the puzzle: in File, Options, Advanced, you can set your "real" Inbox to be the default start up folder.

If you want, you can rename the Microsoft account.

After you set up the account in Outlook, move your appointments and contacts to the Outlook.com data file folders. Hint: it's easier if you use a List view, especially in the Calendar folder. Select all, drag and drop.

If you want to remove the calendar and contacts folder from the .pst your "real" account uses, see Delete Special folders. If you are using an IMAP account in Outlook 2013 or newer, close Outlook and delete the IMAP account's data file. When Outlook restarts, it will create a new data file without the special folders. Don't forget to move the appointments, contacts, and tasks to the Outlook.com folders first.

Configure outlook.com account for syncing

In this tutorial, I'm adding a Microsoft Account that uses the same email address as a POP3 account in the Outlook profile and setting it as the default data file, so the Calendar and Contacts folders are the default folders.

The process is the same for IMAP accounts.

Registry key for Outlook 2010 SP1 and Outlook 2013

Out of the box, Outlook 2010 SP1, Outlook 2013, and Outlook 2016 use the default account for Send to commands but not for new messages created while viewing a data file that is used for delivery. This means if you send a message while viewing the outlook.com calendar, it will be sent via the Outlook.com account. This is not necessarily the desired behavior when you are using an Outlook.com account only for syncing calendar and contacts.

Outlook 2016 users can make this change in File, Options, Mail. Look in the Send messages section about two-thirds down for Always use the default account when composing new messages.

For Outlook 2010 and Outlook 2013, you'll need to set a registry value to always force the use of the default account.

To force all new messages to use the default email account, regardless of which data file you are viewing, browse to the following registry subkey in Outlook and add a DWORD named NewItemsUseDefaultSendingAccount:

Outlook 2013:
HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\Options\Mail
DWORD value: NewItemsUseDefaultSendingAccount
Value: 1

Outlook 2010
HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Options\Mail
DWORD value: NewItemsUseDefaultSendingAccount
Value: 1

 
If you prefer not to edit the registry yourself, you can run a registry file to set the NewItemsUseDefaultSendingAccount key:

Outlook 2013 Outlook 2010

Meeting Requests

The registry key above changes the account on all new messages to the default email account but does not apply to meeting requests. For this we need to use a macro. This goes in ThisOutlookSession.

See How to use VBA Editor for instructions.

Private WithEvents m_Inspectors As Outlook.Inspectors
Private WithEvents m_Inspector As Outlook.Inspector
 
Private Sub Application_Startup()
  Set m_Inspectors = Application.Inspectors
End Sub
 
Private Sub m_Inspectors_NewInspector(ByVal Inspector As Outlook.Inspector)
  Set m_Inspector = Inspector
End Sub
  
Private Sub m_Inspector_Activate()
Dim olNS As Outlook.NameSpace
Set olNS = Application.GetNamespace("MAPI")

 If TypeName(m_Inspector.CurrentItem) <> "AppointmentItem" Then
  Exit Sub
 End If

' so it doesn't fire when you open a meeting 
If m_Inspector.CurrentItem.CreationTime < Now() Then
  Exit Sub
End If

' (1) this the default account
If m_Inspector.CurrentItem.SendUsingAccount <> olNS.Accounts.Item(1) Then
Set m_Inspector.CurrentItem.SendUsingAccount = olNS.Accounts.Item(1)
 m_Inspector.currentItem.Display
 End If
  Set m_Inspector = Nothing
  Set olNS = Nothing
End Sub

Add your email account to Hotmail or Outlook.com

I DO NOT recommend using this method at this time. Outlook.com is using an ugly address (outlook_alpha-numeric-id@outlook.com, or as I call it, outlook_ugly@) as the From address, not the "Microsoft Account" address. Keep both accounts in your profile and use the registry key above to force Outlook to use the default account as the default for all email.

If you use a Microsoft Account from another domain and want to bring your email into Hotmail or Outlook.com, log onto your account using a browser, go to the gear icon (next to your name) > View Full Settings > Sync Email and add your email account as a connected account. Outlook.com will sync the account and store a copy of the mail in your Outlook.com mailbox.

If you do this, you can read your email online, at outlook.com as well as in Outlook. You should remove the connected email account from your profile, otherwise you will have duplicate messages in Outlook.

If you send mail through the Hotmail servers, some antispam filters may reject email from the account because the address is not a Microsoft domain but using Microsoft SMTP servers. (Yahoo Groups rejects messages sent using this method.) If you control your own DNS you should add an SPF record for hotmail. The SPF record you need is v=spf1 include:hotmail.com ~all