Can you give me more info as to why you can so I can understand... ?
Example: On yahoo messenger 11( I also use this)....
1) You open YM
2) You click Contacts
3) You click Add A Contact
After this you get a box asking for the user name or there email address right? If yes, what happens if you try to add them here? Does it say it does, does it give an error message/code?
Thanks! Let me do some research on this and get back to you.
Your Welcome! I just came across this page from yahoo on a fix that should work this issue out for you but we will only know after you try this. I will continue to research this issue while you try these steps below for a "workaround" ...
I see. I just went through everything on yahoo messenger for its settings and there is nothing that you could check/uncheck to make a difference.
One thing I would suggest (but needs your approval) is to sign up for a new yahoo id. I remember one time I signed up and had an issue (sort of like this one) but not exactly and I just deleted it and made a new one and everything was fine.
Sometimes when people abuse the rights of yahoo's policy they strict the id and etc and who ever uses that id normally gets stuck with those same restrictions. This is not the case in every case such as the issue you have here.
So if it is ok with you, sign up for a new yahoo id (even for temporary use) to see if the same thing happens, or it works like it should. If it works like it should then you know there is something wrong with your old id, but if it does not, then there is something wrong with your computer.
New ID - http://new.mail.yahoo.com/addresses
Delete Old ID - http://help.yahoo.com/l/us/yahoo/my/registration/edit-130.html
Your Welcome! I'll will be here so just keep me posted and take your time.