I've been having trouble saving my contact groups with the Windows Live Mail desktop client.  I noticed that some contacts had been "lost" and I tried re-adding them.  When I save the group, it shows up properly on the screen.  But, when I re-edit, most of the contacts are lost and emailing to the group does not email all contacts.  Also, some groups appear to have members, but when I try and write an email, the WLM client tells me the group is empty.

I can go to Outlook.com and see that they are there, but the desktop client refuses to work properly.  Is there a repair tool I can run or something?  Do I have to reinstall Windows Live Essentials?