This is happening with me too. Hope this is going to be solved soon. So far when someone tries to get back in they aren't able to get on and on the host pc it shows that there are multiple users connected(1 for each attempt). The only fix I have currently is to either restart the host computer or have someone with access of the host computer turn off access to log me in and then start it again. It seems that this is an issue with mac from what I can tell. Host is a pc and the client is a mac. Don't have issues when both the client and hosts are pc's.