After just reading Tony Still's question about the High Sierra root bug (Nov.29, 2017), my question is about my Dad (once again) who has installed High Sierra (I still haven't but I haven't installed iOS 11 on my iPhone and iPads yet either 😖 ) I'm now wondering whether anyone has an opinion on whether one should turn off their iMac each night, or leave it running on sleep mode as my Dad does? Could not switching it off (never in his case) allow hackers more easy access than to get in the habit of switching off? He is continually connected to the wi-fi. He does use his machine daily (whereas I do not). I'm sure this question has come up before so apologies in advance for a non-technical but more human useful query. Thanks all!
I think a sleeping Mac is reasonably safe from remote attack as long as all sharing options are off (I'm not 100% certain so if anyone knows better...).
Turning off sharing is good discipline anyway, for all the services that you don't use (most of them for most of us). Go to System Prefs > Sharing and untick everything on the left-hand side that you don't need (I have them all unticked personally); you will need to authenticate with an admin password first. You can also turn on the Mac's firewall to complement the one in the WiFi router by going to System Prefs > Security & Privacy and choosing the Firewall tab.
With those done, I would be happy to leave my Mac on overnight if there were good reasons (like simplifying someone's life): the additional risk is small.
And I am an iOS 11 fan, especially on the iPad - I think that's where all the talent has been working so go for it! High Sierra still looks a bit rough round the edges so, lacking a good reason, I'd wait for the .3 release (.2 is just out and it all still feels a bit Beta quality sadly).
If the reason for leaving the machine on all the time is to avoid the long boot up time, why not swap the hard drive for a SSD, boot time will be reduced to about 30 seconds or so and everything will run much faster (disk based I/O activity).
Georgia Cheer 