Open the project, find the collaborator in its people list, and remove them - they lose access to that project right away.
The steps
- Open the project card.
- Go to its collaborators / people list.
- Find the person and choose
Remove.
Once removed, the project no longer appears in their SyncNow and they can no longer work on it from any PC. Their past entries stay on the shared activity timeline - the history is append-only, so removing a person does not erase what already happened. That is by design, so the record stays honest.
If someone is in the middle of a live work session, it is cleanest to let the session end (or revoke it) so the project returns to Free tidily. If you only want to limit what they can do rather than cut them off, change their role instead. Removing a collaborator never touches your files or your FTP credentials, which stay in the cloud vault.