Humax just a few months old, Now losing schedule every couple of days, sometimes overnight. does not lose the recorded programs, this even happens when the program has been scheduled manually, ie not using the EPG.
Have had a 9200 for several years and never had this problem before. Any ideas?

Can you post which firmware version your 9300 has, and whether all scheduled events are removed each time or just some ?
Just a guess here, but there was a version before the current v1.00.23 which would frequently and unnecessarily offer you to rescan for changes to the channel lineup, this action likely removing programmes from the schedule.

There's a repeat of the PVR9200 version 1.00.23 next friday, it's likely that repeats of those for the PVR9300 and PVR9150 will follow, see here. just make sure the PVR is set to update, or initiate it manually during the relevant period,

Hi. The Hardware is Rev. 1.0
Software UPTTF 1.00.23
System update May 24 2010
Loader ver. a4.38

Ours did this regularly until recently. not only did the schedule go but the settings would return to default values.
Recently did a full reset and rescan of channels and has only happened once since, also changed our booster which has improved signal quality.
Have no idea what was causing it though.

Happened to me many times since I got the thing 18 months ago. No rhyme or reason to it, it seems. Sometimes it'll go for weeks without doing it, then 2 or 3 times in the same week.

Its like it has some kind of freakout over night, and resets everything. I hoped that update thing a few months ago would be a cure, but no.

Every time it 'resets' I have to alter ratio, start/end times, favourites, most of the misc settings, and remember what I wanted to record. Hence I usually don't bother setting it to record things too much on advance, usually only 2-3 days.