By default, Quicken will attempt to set up transaction download when you add a new account or financial institution (see also Adding accounts).
However, if you've been using manual entry accounts and want to try downloading, if you've converted from Quicken Windows or Quicken 2007 for Mac, or if you've experienced problems and had to disable downloads for one or more accounts you may need to set up an existing account for automatic download.
...
If your financial institution is listed under the Already Set Up tab but you are still unable to download by clicking the Update All Accounts button or menu item, then you may need to deactivate this (non-working) account and then return to the Set Up Transaction Download view to reconnect. (You can deactivate downloads for an account by going to the account register, clicking the Settings icon in the bottom right corner, and unchecking the "I want to download transactions" option on the Account Settings sheet.)