Tuhi, your storage assistant · When Tuhi doesn't help
Why does Tuhi say to connect a cloud account first?
Short answer: Online-only only works for cloud folders Storage Studio can see on your Mac. With none present, Tuhi asks you to connect one first; once you have, it lists the folders it sees and offers Keep Cloud Online-Only.
Keeping downloaded files online-only only works for cloud folders Storage Studio can see on your Mac. When there aren't any, Tuhi asks you to connect a cloud account first.
Once you have one — for example iCloud Drive, Dropbox or Google Drive set up on your Mac — ask again and Tuhi names the cloud folders it can see and offers Keep Cloud Online-Only. Files stay safe in the cloud and download again when you open them.