Why can't I add a tenth user to my Trello board?

[Jessica]

I have the free version of Trello, which limits me to 10 users per board.
There are currently 9 users on the board, but the system blocks me and refuses to add the tenth and final user as if the limit had already been reached. However, this shouldn't be the case since there is still one available spot on the Trello board.

[Andy Gladstone]

@Jessica welcome to the Atlassian Community.

The user limit is per workspace, not per board. If you already have 10 members in your workspace, which may contain multiple boards, you may already be at the limit of (10) collaborators.

This article has details on how the user limits are applied:

https://support.atlassian.com/trello/docs/workspace-user-limit/

Good luck! 

(I hope this helps @Ruth as well).

[Ruth]

Hi Jessica, I have the same problem. There is a silent member attached to the Board named Robert King that isn't anyone I know. I am unable to delete "Robert" s he does not appear on  my members list. I'd be interested to know how he got there and how I can get rid of him!

[Caity]

Hi @Ruth, have you also checked the Guests list for the Workspace? If this person is a member of a board in the Workspace but not a member of the Workspace itself, they should appear in that list.