Half
This radical is the same as the kanji, so it means half. This even looks like a few lines getting split in half. See how the top one is actually broken in half too? That's why this is the half radical.
An update is needed before you can continue but you have more than one WaniKani tab open.
Finish up what ever you are doing on the other tab(s), then close them to continue.
The update will complete automatically once the other tab(s) are closed.