Trial court’s failure to instruct jury that prior spousal rape must involve force or violence requires reversal of conviction for failure to register as a sex offender. Mason was convicted of failure to register as a sex offender. The jury found two priors true—a spousal rape (Pen. Code, § 262, subd. (a)(1)) and failure to register as a sex offender (Pen. Code, § 290, subd. (b)). On appeal Mason claimed in part the instruction on failure to register prejudicially omitted a required finding the crime involved force or violence, and that the evidence of such was insufficient. Held: Reversed. Sex registration is required for a person convicted of violating section 262, subdivision (a)(1) when force or violence is used and the defendant is sentenced to prison. (Pen. Code, § 290, subd. (c).) The information did not allege a specific registration offense or the use of force or violence in the spousal rape. No evidence of force or violence was introduced and the jury was not instructed of this required finding. The instruction omitted an element of a specific registration offense and was prejudicial. (Chapman v. California (1967) 386 U.S. 18.) Even if a properly instructed jury might not have acquitted Mason, a correct instruction may have resulted in a hung jury, which is a more favorable result. “Because the evidence was insufficient to prove that [the spousal rape conviction] involved force or violence” Mason cannot be retried for failure to register.