Archived files which have the following icon are able to be restored.
Expired files on the other hand have been deleted from our servers and are no longer able to be restored. The icon for expired files is shown below.
By default all uploads will expire unless you check the box for Auto-archive on expiry. This is available when initially uploading files under the option for "Auto expiry date" on the right of the screen. You can also update the setting once the files have been sent by clicking on the property "Auto-archive" in the upload properties to the right of the screen.
When you look at the list of your uploads you will see the icon for the current state of the files in that item. There are a number of icons that can be displayed here. To see all available icons that can be displayed click on "Sent" to display the Sent items dashboard. Look at the section under "Message Status" for the icon descriptions.