Depending on your cable box, it may take a while to reload the guide data into the box's internal data base. That's what happens when our (Time Warner, now Spectrum) Motorola boxes re-boot. It takes hours to fully reload.
I'm about to go through a re-boot cycle right now, too. Due to our downstairs remodel, I'm moving my cable box and TV upstairs right this minute. Just got the coax hooked up so I can now move the cable box and let it start the re-boot.