Dear Stephanie, As a Workfront partner involved in multiple implementations, I usually have active accounts in multiple instances at once. The e-mail (username) used to register the person must be unique across all instances. However, the e-mail is case sensitive. So... PersonA@mymail.com counts as a different e-mail to Persona@mymail.com which is different again to PersonA@MyMail.Com Having logged in using a valid e-mail account, they will only see the Workfront instance associated with that e-mail account. They will not be able to see a combined list of projects from both instances. I believe SSO might bypass this (so if the e-mail is used in one Workfront instance, and then that same e-mail is registered for SSO the same e-mail may work twice) but I have not exhaustively tested that. Even so, they will only see one instance's projects at a time. It may be interesting to note that Workfront Proof works differently. In Workfront Proof you are a user in one instance only. Any reference to your e-mail after that makes you a 'member' rather than a user of subsequent instances. But from one instance you can see all proof's you have permission to, regardless of origin. Perhaps it's time for an Idea Exchange request to have Workfront behave like Workfront Proof for multi-instance users. Barry Buchanan Work Management Australia