"Debugging and troubleshooting", "List of MyChat Client errors", "Error #0018".

 

Error

Error #0018: a user with this UIN (XXX) is already in your contacts list

 

Error description

An error occurs when you are trying to add a user in your personal contact list but he is already there.

 

Problem solution

Check you list. This user is already in your contact list in one of your group.