If you go back to use the Online version you can upload the return to the "My Docs" storage tool HOWEVER if you ever stop using the Online version you will lose access to all the stored files. So it is always better for you to keep your own files on your computer and to more than one removable storage unit.
Does My Docs™ automatically store my tax returns?
Yes. My DocsTM not only lets you upload and store up to 100 MB of your own tax documents (scanned receipts, W-2s, and things like that), it also stores all the TurboTax Online returns filed using that account.
