Windows Live Mail Sync Issue

My wife and I have been using WLM for email and Calendar for a number of years. We have a Laptop running Vista and a Desktop running Windows 7. We use this as an email client although we use Rogers Yahoo Email. Both email accounts (Dianne and Andrew) are set up as POP3 and are functioning properly. But the Calendar and Contacts which have been syncing between the 2 machines up until about 2 weeks ago are no longer doing so. When WLM is open and I sync on all email accounts there is no problem. But when I press Sync Everything an non-specified error occurs and the Calendar and Contacts are not syncing either with the other computer or the Outlook.com site account

This happened in mid August as well and I logged in to our Outlook.Com site account and reset the sharing permissions to Co-Owner and that seemed to immediately solve the problem.
I have tried the changing the same setting a number of times this past two weeks and have not had any success.

I do not think that this is machine specific because we can make a new Calendar Entry on the laptop and it does not appear at Outlook.com nor on the Desktop. Same for the reverse. A new entry in the Outlook.com Calendar does not update on either machine

Any suggestions?
Thank you
Andrew

That has never been the case here. The calenders would sync as soon as the WLM client opened. We did not see this error before except as described in my above post

No still on 2009

Password issue solved