Windows 8.1 Surface Shuts Down instead of sleep

Thanks Squirty33, but this update has been applied (cancelled first time, then successful straight afterwards).

I found another thread that said to try this:-

Have you altered the wireless network card in Device Manager to not allow the computer to put the device to sleep to save power via the Power Management tab on the card? I had inadvertently done this and it caused my Surface Pro to not wake properly.

To clarify for anyone else running into this:

1. Open Device Manager from the Control Panel or however you normally open it
2. Expand Network Adapters and double click Marvell Avastar 350N
3. Choose the Power Management tab and make sure the checkbox is checked for Allow the computer to turn off this device to save power

But this was already set for me. The keyboard thing must be a red herring as today I got the same problem without a keyboard attached. Having trawled through the event logs for when the sleep, hibernate, restore is successful vs when it isn't, I have noticed that when it isn't I get an  Error 8033

The browser has forced an election on network ......

because a master browser was stopped

No idea if this is relevant????

Hah! Just after I tell you to check to see if you got the update, it happened to me again! I have my power button set to hibernate. When I pressed the hibernate button, the screen faded to black as normal... And then the computer suddenly started to boot again with the event log that the previous shutdown was unexpected (the hibernate failed and my computer did a hard-restart).

My hibernation has been working fine for over a month, but suddenly it's failing again? I have had no windows updates, other than windows defender definitions, since Nov. 16. :(

Looks like they may have not completely fixed this problem with the 2013-10-05 update, since it's still happening. Before the 2013-10-05 update, the problem was happening consistently, every time I hibernated... now it seems to be rare, but still occurring...

Mmmmm, I think there are some problems in this area. I have just been changing the settings for turning off display, sleep and hibernate and never gets past turning the screen off. Not good for battery life. Do post back if you discover anything.

I don't have a key board attached and mine is still shutting down instead of going to sleep.

My computer was shutting down unexpectedly when I put it to sleep. I fixed this problem by going to Choose what  the power button does. Then I set it to Shut Downand saved it. Then I pressed the button and the computer shut down. After turning it back on, I went back to Choose what  the power button does and switched it back to Sleep. now it works for me!