Organizing and accessing contact information in Outlook.com
This is what I'm facing, too. Terrible coding in Link to Windows results in about 600 contacts being over 20000 instead, with many duplicates all tagged with "(contacts synced by Link to Windows)". There should be an easy way to delete all of them, but nope. Just criminal. Microsoft should have to compensate all of us for the time it will take to recovery from this bug.