I’ve had this issue various times, the problem is that every time you add an event in Windows Live Mail, it simply disappears. No error, no notification. The event is not added. The issue is a bug which for some reason has skipped rectification. However, there is a simple work-around:

On your Windows desktop, do the following:

  1. Control Panel
  2. Clock, Language and Region –> Region and Language (Windows 7) or Region and Language Options (XP)
  3. Change the Short date & Long date format to d MM yyyy

Screenshot:

windows live mail live calendar sync problem 

Note: You may use dividers like / or .

The trick in simple terms is to change the date formats to numbers. Once done, restart Windows Live Mail and all should be good. :)

~Enjoy