I left it alone for about an hour. It put itself to sleep without any intervention from me. Instead of finding it asleep, I found it at the empty Boot Manager. Power cycled it and logged in. Thanks to Word’s autosave, I didn’t lose anything.
What kind of surface are you leaving it on? Carpet or something like that where the ventilation might be messed up?
I’m having the same problem. Plugged in, unplugged, not good. I have the WD850 2tb, FYI.
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Mine is on top of a metal case desktop that is turned off.
I had it on a table, and a desk. No carpets or blankets or stuff. At least one of those times, the fan was running, and the case was hot. Maybe it’s the hard drive?
My guess is you may be seeing something some other of us have: Laptop Overheating and Losing Connection to M.2 Drive
The WD Black SN850 2 TB specifically can get too hot for the laptop and cause it to d/c. At least from what we’ve seen.
I will say that one of the first things I did was install the WD tool for the SSD and update the firmware. I seem to have less issues than others.
Should I return the WD 2 TB? I wouldn’t have bought it if I had read this.
That’s really up to you. Have you tried updating the SSD firmware with the WD utility?
I figured worse case I could throw it into a TB4 enclosure and use it externally so I kept mine.
I will try that. Maybe. Today is the last day of the 30 day return period. I requested a return, but have not received a response.
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We believe we have root caused this to an SN850 firmware issue on some version of the firmware. Updating the SSD firmware has resolved the issue in each case we have come across: My system is rebooting to a “Default Boot Device Missing or Boot Failed” message
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Win 10
driver bundle installed
brand new, couple days old.
If I close the lid, whether plugged in or not, for more than say 20 minutes?
I open the lid to it rebooted, and a message. Pic as soon as I figure out how. 
Default Boot Device Missing or Boot Failed. Insert Recovery Media and Hit any key
Then Select 'Boot Manager to choose a new Boot
[Ok]
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We believe we have root caused this to an SN850 firmware issue on some version of the firmware. Updating the SSD firmware has resolved the issue in each case we have come across: My system is rebooting to a “Default Boot Device Missing or Boot Failed” message
2 Likes
I installed a new WD Black SN850 2 TB. Installed Windows 10. Installed all updates. Changed settings to display only on external monitor. Changed power setting to Do Nothing after closing the lid while plugged in. Shut lid. Came back 3 hours later and it wouldn’t come to life. Clicked keys, clicked mouse, nothing. Case was too hot to handle. Power switch light was blinking. Held power switch down until light went off. Started machine. Fan kicked in at high speed. Case cooled down and fan went quiet. I’m concerned I may have shortened the life of the unit.
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I just got the laptop today. I have windows 10 installed. I closed the lid and plugged it in and tossed it on the bed. I came back an hour later and the fan was spinning extremely fast and since the vent was facing the bed covers, it couldn’t breathe.
How do i just make it sleep/hibernate and not try to cool itself down? Or am i missing something. Thanks!
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Is Windows set to suspend if the lid is closed?
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I’ve seen this issue with other brands. Maybe some application was preventing sleep?
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