The Windows 8.x Standby / Wakeup from Sleep Problem:
Some time ago I set up multiple Dell Optiplex 9020 mini towers with Windows 8.1. After testing standby / sleep mode I noticed a very strange and annoying problem: Whenever the PCs are waken up from sleep (standby) all connections to open network shares and open Office 2010 documents are lost. All shares are on a Windows 2012 R2 ESSENTIALS server + domain controller which runs as a Hyper-V VM. So after waking up a Dell 9020 from standby I get my Win 8.1 login prompt, log in, but for any open shares that were open when the PC went to sleep in explorer, now I randomly get either a domain authentication error message or a new authentication prompt that asks me for domain username and password. The connection to open Word 2010 docs is always lost and Word tells me that the computer came back from standby but a connection problem occured and the document is now read-only, i.e. it must be saved as a new document. Very annoying!
What I tried (without success):I googled around a lot and found some hints that might be related to the problem:
1. Many people recommended to go to network adapter settings in device manager and completely disable standby for the network adapter, i.e. uncheck "Allow the computer to turn off this device to save power". I found out that similar suggestions date back to Windows 7 or even XP. Unfortunately, this did not help. I also tried tweaking some more advanced power settings of the drivers but without success. The problem remained. BTW, I don't see the "computer can turn off this device to save power" in Intel's latest drivers anyway. There are some other power management options but not this one.
2. I tried installing the latest original Intel network drivers instead of Dell's. No success.
3. On Dell's forums people reported that there are problems with the Dell Optiplex 9020 I217-LM NICs in standby, flooding the network with packets. The problems were related to Standby, IPv6, or even AMT. But I already had the latest drivers and BIOS and no AMT enabled. So this was not the problem.
4. I tried tweaking some advanced power management settings like hybrid sleep, etc. Again, no success.
5. Maybe the problem was related to IPv6? I tried turning it off but again no success.
6. Maybe it was the virtual Server 2012 R2 domain controller? Turned out this is not the case (see below).
7. Some people reported that a similar problem occurs with intelligent switches. I have a HP ProCurve 1810G. Dell ProSupport could not help me to solve the problem but they confirmed similar problems that could be solved with latest switch firmware updates. Indeed, attaching a simple Netgear gigabit switch seemed to solve the problem. So I spent much time updating the switch firmware and tweaking the switch options and finally decided to buy a brand new Netgear intelligent switch, just to make sure that the problem was not caused by the HP switch. Unfortunately, the same behavior appeared with the new switch.
8. There was a Microsoft Office bug that caused problems when waking up a PC from standby but that should have been fixed meanwhile. A Microsoft fix did not help either.
... I probably tested even more "solutions" but neither did help...
Solution to the Standby problem (cause: VirtualBox Bridged Network Driver):Right before giving up and turning off standby in Windows completely I suddenly found a thread in Microsoft's forums (don't remember the url) where someone suggested that Oracle's VirtualBox may be causing similar problems. And in fact I had installed VirtualBox on each PC because I had virtualized the old XP computers to have them as VMs and to be able to run the old software.
Indeed, the issue was caused by the Oracle VirtualBox Bridged Network Driver. So I disabled (unchecked) it on the network connection (where the IPv4, IPv6, etc. protocol settings are done) and no more problems. The computers now come out of standby and all network connections (shares, open Word docs) are still open. Everything seems to work properly.
BTW, I am using "NAT" with VirtualBox, so I don't even need "Bridged".
Hope this helps!