Hibernation being disabled (perhaps by Windows Update)

I've not been on here much lately, but I've noticed the same thing on 2 laptops in the last 24 hours.

The Hibernation function (which I know was definitely there) is being disabled and the hiberfil.sys is being deleted.

Both machines are running 1703 and the machine is trying to update to 1709 - I keep hitting Remind me Later because I intend to go straight to 1803 which I gather isn't far away.

I'm wondering if the 1709 update is deleting the Hibernation file in an attempt to free up space, but forgetting to put it back again when I exit the Windows Update screen.

Has anyone else seen this?

I've seen the exact opposite recently - each insider build re-enabling hibernation when I explicitly turn it off.

This would fit with your assumption (saving space). They turn it off prior to upgrade and turn it on again irrespective of your previous setting. Assuming 17133.1 is the released spring update (perhaps, perhaps not) you'll find when you upgrade it is turned on again.

Some bug (or resetting of options to default) is going on here anyway.

Thanks for that.

It seems to have disappeared again on one of my machines (where I switched it on last night), so it does seem to be quite persistent!

I don't have too much problem if the default for a new installation is to have hibernation switched one way or the other on a fresh install.

However for me to explicitly turn hibernation on (and use it in that mode for several months), and then have Windows itself later turn hibernation off when I'm not looking, I'm less happy about.

Bree said:

1803 is expected mid-April.

Your 'Remind me later' sounds like you have the Update Assistant installed and, as you surmise, it's probably trying to free up space. This would most likely have been installed by the windows update KB4023814.

This update cannot be uninstalled, but its effects can be undone. See this post...
Block Windows 10 update assistant/all updates

Thanks for that - I'll check it out later.

Bree said:

I never let windows update or the update assistant do my upgrades for me, I always upgrade manually using the install media made by the MCT. I've never lost hibernation that way. In fact, the upgrade always turns Fast Start-up back on (I like it turned off) and hiberfil.sys is essential for Fast Start-up to work,

Yes I tend to do that too, although sometimes I let it upgrade itself.

In this case I want to use 1803 install media (when available) for one of these computers, which could do with a clean install to tidy up/ get rid of the various accumulated bits of software on there.

Callender said:

There's a few third party softwares that might turn hibernation on if set in the configuration file for the program. It can be easy to forget about when launching such softwares.

I don't think I've any software like that installed. Plus I've not installed anything recently and Hibernation (which I use quite often) has worked fine for a long time before suddenly failing at the same time on two different machines with quite different software applications installed.
So I do think it's a Microsoft update which has done it.