Your computers

Log in to the desktop app on each computer with the same email and password. Settings, Account, shows the email you are logged in with, your subscription, and Log out on this computer. Logging out frees that computer; log in again whenever you like.

How many at once

Use it on all your computers. There is a fair-use limit on how many can be active at the same moment; if you hit it, log out on one you no longer use, or ask support to log the others out.

Offline

The app keeps a signed copy of its check-in, so it starts without a connection and checks in again when it has one. The AI itself needs the connection.

From the web

Settings › Security and sign-in lists every browser this account is signed in on — which browser, roughly where, when it signed in, and which one you are reading on — and logs any of them out; Log out everywhere else ends all of them but this one. A computer with the desktop app on it is listed under those, with its name, its version and when it was last used, and can be signed out from here too. There is no live online light: each row says when it was last used, not whether it is switched on this second.