DIRECTV: Rebuilding Scheduler List

We bought a new TV - a Sony smart TV - and we've been setting it up. I didn't understand why DIRECTV wasn't showing on my TV, but it turns out we didn't have the power plugged into the back of the DIRECTV box.

When I plugged it in, the DIRECTV box turned on, but nothing was showing up on my TV. So I turned the box off and then on again. This time, an image popped up on my TV: the DIRECTV logo and beneath it, "Rebuilding scheduler list..."

How does that process work, and how long does that process take? It's been going for an hour already. Are there other things I can/should do? Also, if it takes a long time, do I need to leave my smart TV on all night?