Edit: After half day, my wife’s Mac started having the same problem. I have then applied the solution that I found in the Apple
Reminders App for Mac – new feature!
The new Mac OS X !0.8 Mountain Lion now also has Reminders app,as well as iOS 5.The new thing about this app is that it will bring in its “geofencing” feature to all Mountain Lion-enabled Macs,which allows owners to be reminded by their devices,based on their current location.
On older OS X versions Reminder was an iCal feature.However,with the new operating system,it became an independent application and the iCal was renamed to Calendar.The app’s desktop looks the same as it does on the iPhone screen –- it is a simple window with a list of tasks,where users can simply swipe from their reminder tasks to completed tasks lists.
A triangle icon button at the bottom of the window shows a more complete user options set.It has lists of reminders and a monthly calendar.Another great feature is a search field –- it make it so simple for users to search through their reminders.
In order to create a new reminder a user should click on an information button.Doing this will help to figure out the way in which the app will control the tasks user created.It could be a task reminder with an alarm,or a simple to-do list.When configure a reminder to alarm at a certain time,there will be a note appearing on the device’s Notification Center.
Users can also can also configure the way events will appear in the Notifications panel at the System Preferences.It can either be a banner,that will disappear on it’s own,or an alert,that will stay on the display until the user turns it off.When all the Alert notifications are configured,a window with a Close and Snooze buttons will appear.
Configuring Your Reminder App
A user can create a new reminder by using an information button. This will help him or her to configure how the app will monitor the tasks he or she created. It could either be a simple to-do list or a task reminder with an alarm. Configuring a reminder to alarm at a specific time will appear on the device’s Notification Center.
At the System Preferences, users are also allowed to configure how events will appear in the Notifications panel. They can either use a banner that will disappear on its own or an alert that will remain on the display until it’s dismissed. Once the Alert notifications are already configured, a window with a Close and Snooze buttons will appear.
Latest version of OS X 10.8 supports geofencing,which is an alert feature,that can be triggered based on the device’s location.Though,the system will require a WI-FI connection in order to figure out user’s location.After spotting the location,users can add a new entry via “remind me:at location”,where they can punch in an address or a contact information.Users can use options to be reminded when entering or leaving a specific location.The good thing about geofencing is that users can hook it up to a date and time reminder,which makes it a very useful app.