I've got this problem with Windows Live Messenger 2010. Everytime I add a new contact, it automatically blocks them, then when I right click to unblock, it says "Block Contact" So I have to click it twice to unblock.
After this, it doesn't add the contact, they appear offline. When they try to add me, I don't get an invite. This only happens under one address.
So far, I've uninstalled/re-installed it. Gone into Application Data under my Log on name and deleted the contents of the MSN messenger folder, but I still get the same issue. I've cleaned the registry and cleared all temp files, thinking this may help, but it hasn't.
Does anyone have any suggestions? This is driving me mad.