I find my HwS usually does the guide update as soon after 1:30AM as it sees free time.
Sometimes later it will often do what looks like an update, but does not change the version.
It will then restart and get a new guide copy. Why must it do that twice?
If it has an EHD loaded it may try to examine that drive and can take 1 or more hours.
I try to always pull the supplies on the EHDs to save a lot of wasted time.
-Ken