Windows 10: Missing operating system

OK, I did it too!! Most people have the problem with a laptop with a SSD disk. So had I. I borrowed a 2.5 inch harddisk from another computer. I made an image from my SSD disk and transferred it to the harddisk. I started the laptop from the harddisk and started the windows 10 upgrade from a dvd. And to my surprise the upgrade went well this time!! Windows 10 was activated. After that I made an image from the harddisk with windows 10 on it, and transferred the image to my SSD disk. I placed the SSD disk back in the laptop; windows 10 started and was activated!!! Very strange that replacing a SSD disk with a Harddisk solves the problem. I have no explanation, but I am on Windows 10 now. Next step will be to try a clean install, after making an image so that i can go back in case of failure. Laptop: Clevo W150ER - Intell i7 3630QM 2.4 Ghz - DDR3 8 GB - Samsung SSD 840 120 GB - Hitachi HD 500 GB - Wifi Intell Centrino N135 - Lan Realtek PCI GBE family

 

Did you ever get to windows 10? I had the exact experience. I upgraded and it was working fine. I did an update and ... boom. "Missing operating system" I'm currently rolled back to windows 7. I tried with a new ssd, hdd, fixing the boot records. no luck

 

Did you try changing boot mode in BIOS? Like what I did in this post: Missing operating system - Page 3 - Windows 10 Forums

 

Just suffered from the same problem and after some fiddling resolved it - hopefully this will work for you.

Background:
Been running windows 10 from an SSD for a while - in a multi-drive system. An old HD started to give errors so I removed it and replaced and then the problems started.
Windows failed to boot (cannot find necessary device)

Steps to resolve.
Created a repair disk on a second pc and booted into repair console.
Advanced - repair startup. (Didn't work but worth a try)
Advanced - cmd prompt.
Used diskpart to set ssd as active
D Code: Diskpart list disk set disk 1 set partition 1 active[/quote] You might need different disk / partition. (Still no joy at this point)

Back to cmd prompt in repair

Code: bootrec /fixmbr bootrec /fixboot bootrec /rebuildbcd[/quote] Again still no go.

Tried to used the reinstall option - but didn't work 'disk locked'....

I also attempted to use BCDEDIT to repair the BCD file - but still no good

Code: BCDBOOT c:\Windows /s c:[/quote] Finally got the show on the road again - with a little tidying to remove references to the old drive - all was still in place....

Good luck

 

I read through a lot of the messages in this thread. I was getting pretty worried that I was going to have to do a clean reinstall of Windows 8.1, and then the upgrade to Windows 10 and start restoring from backup (yuck).

But then I had an idea. For the upgrade I had created an ISO image of the Windows 10 upgrade, and then mounted it and copied all the files files to the root directory of a USB drive. That was what I ran to execute the upgrade.

When I got the missing OS message. I first tried turning off and turning on the computer a couple times. That did not help. Then it occurred to me that perhaps the computer is trying to boot from my USB drive which was still plugged in (and was not formatted as Bootable). So I took it out, cycled power again and this time everything proceeded as expected.

Whew!

I hope this helps someone else who, like me procrastinated until the last day for the free upgrade.