PC restarted by itself when it was idle how can i check why in

I was away from my pc the pc was idle
but when I came back I noticed that my pc restarted by itself
I want to know why ?
or if there is something wrong with my hardware
event viewer ?
please let me what I need to search in event viewer
thank you

windows 10 64 bit
i7 6700k
gigabyte z170x gaming 5
sapphire r9 390 ntro 8GB
16 GB ram

edit
I think it restarted between 7 and 7.20 pm (my local time) but I'm not sure
if this help in eventviewer
thank you so much .

dalchina said:

A 'normal' event for Win 10, with no changes to control Windows updates, could be a Windows update requiring a restart.

Most people have probably either set Active Hours to stop that happening for up to 12 hrs (18 hrs in the Creator's Build I believe), or set Windows Updates to notify (for later manual download).

You can check that in your Update History, at least by date.

As you say, examining your event log might also be relevant, though a lot less obvious.

Identifying event id's from a number is easier than finding out what event id's to expect.
https://www.eventid.net/

thank you for answering
please can you tell me exactly what I need to search in event viewer and I will post images from my event viewer here
I just want to be sure its not a hardware proplem
I'm not that good in computer
that's why I'm asking
but tell me what part of my eventviewer you want me to post an images for it
thank you

dalchina said:

Hi, as I said, predicting the relevant event id's for a restart that occurred for unknown reasons is not straightforward. Try searching for 'What is the event id for a restart' for example, and you'll see what I mean.

I can only suggest you inspect the events around the period of interest , looking for a log off, shut down, restart... and if necessary using the link I posted to identify them. Trying to work out why a PC restarted just from the event viewer could be extremely time consuming, depending on the number of events.

If you're lucky and there are few, then it may be feasible to discover something.

First you'd need a list in time order - note that if you simply open the Event Viewer, the reports are categorised,which make tracking something through time impossible. as you know the time period, you could try this:


But easier is to get this free program (title top left) which lists events in order:


Much easier: look at your update history for that day: does it show an update being applied? If so, what is it? Does that update require a restart?

I will post as many images as I can in this post
1-from my update history yes there is an update for today

but can I be 100% it is the update the caused the pc to restart ?
here is some images from my event viewer

here I searched for these events ids 1074, 6006, 6008
I found only 2 for today 15 .6



I searched for this event 6008
which according to this page
Read Shutdown Logs in Event Viewer in Windows Windows 10 Performance Maintenance Tutorials
6008 means Logged as a dirty shutdown
but found nothing


also as you see in the first image I post there is no Critical error which according to the web
when unexpected shutdown or restart happen it will usually result in Critical error in event viewer


I hope these images will help
thanks to this page it helped me a lot find and search the event viewer
Read Shutdown Logs in Event Viewer in Windows Windows 10 Performance Maintenance Tutorials

dalchina said:

Unfortunately your screenshots were not posted.
to post a screenshot please use the Insert Image icon above your post to the left of the video icon.
(Or see the Tutorial section for a guide on posting a screenshot).

Let's try and keep this simple.
1. What was the update you received on the day in question? Does it require a restart?
2. Download and run Fulleventlogview (shown in my post above, free).
Browse down to the day/time of interest, then post a screenshot, full-screen, of that program.
Hopefully the events around that time will include something indicating logging, shutting down etc.


Read Shutdown Logs in Event Viewer in Windows Windows 10 Performance Maintenance Tutorials
Yes, that is helpful if you are looking for particular events. But in this instance, that would only take you to a time when the event you assume occurred did occur. What does that tell you? Well, you already know the time, so that's not new. It only confirms an event of the sort you're looking for occurred at that time- it won't help to tell you why.

here the images again I uploaded them to tenforums as attachments
thank you for your help again
please take a look at them maybe you will find something .

as you can see in the first 3 images I searched for events
6008 1074 and 6006
in the date 15 .6
there is event 1074 and 6006 at time 7.13
but I don't understand what it said
it only say the event log was stopped
also yes according to the update it said you may have to restart your system

dalchina said:

One thing to try: Check your Reliability History at the time of interest. Unlike Update History this give the time an update was applied.

Type Reli in Cortana's search bar. Click Reliability History. Look for the blue i for update reports e.g.


And to confirm:
kb4022725 needed a restart.

What’s New in Windows 10 Cumulative Update KB4022725

the update was applied on 7:14
and according to event viewer there is 2 events 6006 and 1074 at 7:11:53 and 7:13:50
I think I can now be 100% sure that it restarted to complete the update right ??
thank you so much again for your time .