I'm using desktop TurboTax Deluxe. I am working on my state (CA) return and it says that I have an $81 million refund. How start over on the state or delete it?

It sounds like something was overstated. You can double check your state entries in the federal section. Check ‌your W-2 (Boxes 15-20) and 1099's state boxes, and double check all entries, especially the withholding or state tax paid.

If you can't manually find the error, click on the link below for instructions on how to clear and start over. Choose whether you are using the Online or Desktop version. 

How do I clear and start over?
 

If you are using the Online Version, and don't see Left Panel Menu, Tax Tools, right away, open any section of your return, for example your W-2 section, then try again to locate the left panel)

Go back to your federal return and click edit on your W-2's.  Then look at what you entered for boxes 16 and 17 for your W-2's.

You probably left the decimal point out of a state withholding in W2 box 17 or a 1099R box 14.  Go back to Federal  and check your entries.  Or you can switch to Forms and look around for it.  Open the W2 and 1099s.   Did you import the W2 or 1099?  It could have imported wrong.  I would delete it and enter it again manually.  That usually fixes it.