This is the time window within which your event can accept uploads (either from Guests, Hosts, or Collaborators), beginning at the event's start date (which you set) — NOT when the event is created or when payment is made.
The upload window on GuestCam is 12 months, from your event's start date.
This, combined with our multi-gallery feature, means you can use GuestCam for multiple occasions related to your event. For instance, a wedding event can use GuestCam for the Engagement Party, Bridal Shower, and so on, without having to pay separately for each occasion leading up to the wedding.
This window also applies to MagicFind Face Search - if you have the add-on. Found faces will still be available for viewing after the upload window has ended - you just can't search for new faces after this window.