Holiday updates

I founds that the latest holidays are missing from my calendar. I checked for updates but none are there and manually trying to install the latest holiday updates gives an error that the update is already installed or does not apply to my system.
How can I get the latest holidays to show up?

After applying updates that contain new holiday information, the newly included holidays are not directly added to your Calendar. You’ll have to reselect the option to include the holidays for a specific country in your Calendar. To prevent duplicates, it is recommended that you delete the currently imported holidays from your Calendar before importing the holidays again.

Remove current holidays
To prevent duplicates after applying a holiday update, it is best to remove the current holidays from your calendar first. The easiest way to do this is to set your Calendar view to the By Category view;

• Outlook 2002/XP and previous
  View-> Current View-> By Category
• Outlook 2003
  View-> Arrange By-> Current View-> By Category
• Outlook 2007
  View-> Current View-> By Category
• Outlook 2010
  View-> Change View-> List
  Arrangement-> Categories

Now you can easily select all the items that have the Holiday category and delete them all at once.

Import new holidays
To import the new holidays you can reselect the option for the holidays of your country in the Add Holidays… dialog;

• Outlook 2007 and previous
  Tools-> Options…-> button Calendar Options…-> button Add Holidays…
• Outlook 2010
  File-> section Options-> section Calendar-> group Calendar Options-> button Add Holidays…

Holiday updates
Below you’ll find a list of the latest holiday updates supplied by Microsoft.

• Outlook 2002/XP
  Includes holidays from 2006 to 2012.
• Outlook 2003
  Includes holidays from 2007 to 2012.
• Outlook 2007
  Includes an update for the date for Jewish Memorial Day.

For holidays beyond 2012 you can download this file. It includes holiday information from 2009 up to 2028.
See below for more information on how to import the holidays included in the zip-file.

Manual holiday updates
Outlook holiday files have the .hol extension. If you have an updated hol-file that you wish to use with Outlook, then you can simply double click it to to launch the “Add Holidays to Calendar” dialog. You can use this method for instance to import custom holidays or vacation lists provided by your company.
When you create a hol-file of your own, make sure you save it in the Unicode format (use the Save As… option when using Notepad).

If you want it to replace the holidays list of Outlook, then you can overwrite the outlook.hol file that is located in the language ID folder of the Office installation directory. For instance;
C:\Program Files\Microsoft Office\Office12\1033

Note 1: To look up the language ID folder for your language you can use this table. You need to look in the "LCID Dec" column for the correct number.

Note 2: If you are using Outlook 2000 or previous, then the holiday definition files are saved in a txt-file and the default file is called outlook.txt. Also, this file must be saved in the ANSI format. Because of the txt-extension, the aforementioned double click method will not work. Instead, you’ll have to place it in the language ID folder of the Office installation directory and use the Add Holidays function in Outlook.