I’ve been using a Dell Latitude E6400 laptop for work recently. Each night, I typically hibernate my laptop so the next day I can resume where I’ve left off, avoiding the whole shutdown and subsequent power-on sequence. It has served me well in the past. However, lately I’ve found my laptop sometimes powered on in the morning and sitting at the unlock dialog as if I had pressed the power button to wake it up. Strange, right?
I know about Wake-on-LAN, but all of those types of settings in my BIOS are disabled, and surely I would have to intentionally have a device trying to wake the thing up even if those settings were enabled. So I did some searching. Some people had complained about a version of the BIOS causing the problem, specifically noticing that at midnight the laptop would turn itself back on. While my BIOS version was much newer than the one to which they referred, my problem wasn’t exactly the same, because it didn’t necessarily happen every night and it did sometimes happen during the day if I were to hibernate it in the afternoon.
More searching found this post which reveals the more likely culprit to be the settings on the Intel network adapter.
Seen here, there are additional Wake-on-LAN settings in the Power Management tab (turned on by default?) of my network adapter’s device properties. I don’t know how specific this is to my particular model of laptop, but if your machine also has an Intel 82567LM network adapter, this probably is relevant to you.
To get to it, go to Control Panel → System → Hardware tab → Device Manager button → Network Adapters → Intel(R) 82567LM Gigabit Network Connection. You can see the familiar-sounding options, including “Wake on Directed Packet”.
Wake on Directed Packet
Enables this device to bring the computer out of standby or hibernation when a packet is sent directly to the adapter.
For example, any attempt to remotely access files stored on the computer will wake it.
I imagine this could mean any networked device, like a TiVo, scanning the local area network would trigger the laptop to turn back on. I don’t anticipate using this feature, so I definitely don’t want it turned on. I turned off the three options there that also includes the “Wake on Magic Packet” options. I expect this to fix my automatic wake up problem and will know tomorrow if I need to revise my findings.