Once Safe Search is disabled, it will stay that way until you turn it back on again. ("Filter explicit results" is unchecked and "saved".) Maybe you need to turn it on again first.. See the link below:
Hope this helps.
I am running windows 7 & I E 9. For the last two weeks, the option to turn off safe search has disappeared. If I click on the gear, then search settings, the only option I find is to turn on and lock safe search. The sliding bar to slide onto "no filtreing" seems to have disappeared. Can someone please help!