If I have lived and earned abroad for that past 5 years, must I file a State return?

Which state and have you abandoned your home state entirely? 

Do you have no credentials, such as a driver's license, voter registration, et al?

Normally, if you have abandoned your domicile (your main, primary home) in that state, and you have established a new domicile in another state or country, and you have no income sourced to your previous state (such as rental income from a property located there), then you no longer have any obligation to file a tax return in that state.

California.  I have California drivers license, voter registration.  Thanks!