Newbie Question: Erratic Sleep/Logoff behaviour

[cleanup]

Can someone please explain to me how OS X handles its sleep behaviours? It sleeps even when I have applications actively running... why? I set it to never sleep, but when it woke up this morning (by settings), I wasn't there, and eventually, instead of just going to screensaver, it slept. I clicked the mouse, the log in screen appeared, I logged in, then the screensaver appeared and I had to unlock the computer again.

Whaaa'? I'd really just like to know how to prevent the Mac from sleeping when applications are actively running (like BitTorrent downloads, for instance).

Thanks in advance.

 

[croshtique]

Odd behaviour - double check your sleep prefs (System Preferences > Energy Saver) to make sure you've set it to never sleep (and haven't got it confused with the display sleeping for example)

 

[stridey]

Also, know that your energy saving prefs are only for your user. So when it's at the login screen it will go to sleep eventually, no matter what your settings are.

Also, if you have a laptop, realize that there are two energy saving settings: one for plugged in, and one for running on battery power.

 

[Linkjeniero]

I'd really just like to know how to prevent the Mac from sleeping when applications are actively running (like BitTorrent downloads, for instance).

Thanks in advance.

I don't think you can do this, because the computer is ALWAYS running something, even if you think it's not, and it doesn't have a way to tell appart the apps you want running from the ones you don't care. If you want it to stay awake, just set it to never go to sleep on it's own... and as you were already told, keep in mind that this settings only take place AFTER you log in, and they change if you unplugg the computer (you can set it to never sleep on battery too, but I wouldn't recommend it; and you can also set it to auto-login).