I am using an add-on graphics card: Nvidia Quadro K1100M on top of the onboard Intel HD Graphics.

By design, the M3800 only wakes up by pressing the power button.

If this is not happening, can you check if you are using the onboard graphics card or an add-on and also the OS?

does it wake up by pressing the power button?

Lee - I am having the same issues and updated everything like you did.  When my M3800 goes to sleep, it does not wake up.  I have tested with nothing plugged in (no power brick, usb or anything), everything plugged in (dock, power brick), using the power button to sleep it, using the start menu to sleep it, and it never wakes from sleep.  I have to hold the power button down for 10 seconds or so, let it force power off, then press the power button for 1 second and it lights up and powers on as a new start.

This didn't use to be this way, but I can't pinpoint any certain update that caused this.  I used to be able to close the lid, walk to another office and open the lid and begin where I left off.  Can't do that anymore.

Help please.

Karl

Been working on this issue for quite a while but getting no response from case owners.

Suggested troubleshooting is to rollback video drivers. If not available, download recent, not the latest, from manufaturer's website.

For example, if your M3800 has no add-on graphics card. go to https://downloadcenter.intel.com/SearchResult.aspx?lang=&ProductID=3720&ProdId=3720

and download the drivers tagged

Release Date: 10/3/2014

Version 15.36.7.3960

Please update what happens next

Recently I started having the same issue - not being able to wake from sleep without holding down the power button for 10-20 seconds.  Is there any fix if I do have additional Quadro K1100M graphics card?

I'm having the same problem but also trying to resolve an issue with HDMI output resolution being limited to 1920x1080. I've just found this thread and wondered if they're related. There's a new driver available - see final post in thread.

https://communities.intel.com/thread/55105

Exact same issue...Issue started after upgrading the Intel HD Video Driver 10.18.10 3993 yesterday.  Downgraded the driver and the problems still exist.  No issues previously.

I contacted Dell and they are replacing the motherboard this week some time, hopefully.  I'll post if that fixed the problem after they are done.  Thanks - Karl

The suggested fix is still to roll back drivers to those released from late last year.

There seems to be some reported conflict with the new updates & the processor.