You cannot file multiple returns in one online account. Never start another return by going back and overwriting everything in the return you just filed. This will replace your info, which means you won't be able to retrieve your return later. If you wish to use the Online product to file additional returns, you'll need to create additional accounts

 If you're preparing multiple returns for family members, it's more economical to switch to the TurboTax CD/Download software, which lets you e-file up to 5 federal returns at no additional cost.
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