On a rainy day, could you (or others with this automatic birthday calendar trouble) please test the following?
Shut down the phone and any applications using live.com i.e. Windows Live mail.
Log in to people.live.com
Unlink the connection to Twitter, Facebook etc.
On people.live.com select all the local contacts and create a .csv backup from the menu.
Store the backup safely!
Select all the local contacts on people.live.com and delete all.
Select calendar.live.com and remove the automatic birthday calendar from the settings.
Log out from live.com
Create a copy of the contacts .csv file (for safety) and inspect the copy for weird characters, erroneous extra white space, and that the contacts birthdays appear correctly in i.e. Notepad. It looks a bit messy, and this step can be omitted if you are not
sure what I am talking about. The file looked OK in my case.
Log in to people.live.com
The contacts list should appear empty, with an import option at the bottom.
Import the contacts from the backup .csv file - the guide asks if everything looks OK and also have an option to merge duplicates. Inspect and complete the import.
Select calendar.live.com and enable the Birthday calendar.
Select the main calendar and check that the contacts birthdays appear. It may take a minute or two to refresh - or it can be forced to refresh from the settings menu as discussed previously.
Log out from live.com
Start up the phone
In settings -> mail + accounts - long press the Microsoft account and select sync, if it is not sync'ing already. It takes a while to complete.
The contacts and birthdays of the contacts on the phone should now appear correctly.
Notice: The carefully collected thumbnail images of my local contacts are gone after this.
The automatic birthday calendar now works as advertised for me during a week and lots of sync'ing and testing on live.com, on the phone, and in Windows Live Mail: New contacts with birthday details appear in the calendar automatically, and changes to existing
contacts also reflects in the automatic birthday calendar.
I still have no idea what caused the flaw to appear in the first place after working correctly for months, so it may prove a tough one to debug in the Microsoft labs (and I will let you know if/when it comes back) .
Now link Twitter, Facebook etc. back to the Microsoft account from mail + accounts, showing "Attention required" or from the guide on people.live.com if you want.
Please report back later if you went for this drastic step, both if successful and also if it did not work for you?
Disclaimer: Always store an extra backup of everything important.
--
Hans