Question Deleted a partition, now I can't boot Windows 10 ?

[Petros_K]

I had a dual boot setup: two partitions on my SSD, one Windows 7 the other Windows 10. Before making a change I was given the choice to boot either. However, using Disk Management I deleted the partition with Windows 7 on it wanting to merge the free space with the partition containing Windows 10. When I tried to reboot the computer, I can no longer boot.

I tried booting by running a USB Windows 10 Media Creation Tool, which gave me the option to repair, but it could not repair. Any option available now other than complete reinstallation?

 

[Lutfij]

By any chance would you happen to have a screenshot of what Disk Management looked like? I hope you've backed up your data as you'll need to reinstall the OS.

 

[artk2219]

I had a dual boot setup: two partitions on my SSD, one Windows 7 the other Windows 10. Before making a change I was given the choice to boot either. However, using Disk Management I deleted the partition with Windows 7 on it wanting to merge the free space with the partition containing Windows 10. When I tried to reboot the computer, I can no longer boot.

I tried booting by running a USB Windows 10 media creation tool, which gave me the option to repair, but it could not repair. Any option available now other than complete reinstallation?

You could use diskpart in the windows install media to create a small boot partition on the drive. It can be a little bit of a pain, but you should be able to get it to boot back up. Worst comes to worst, back up your files and start fresh. Eh backup your files regardless just to be safe before attempting anything honestly.

https://www.reddit.com/r/buildapc/comments/uk0ymt/rebuild_windows_boot_partition_on_drive_with/

 

[Petros_K]

I think through a series of booting the USB Windows 10 Media Creation Tool, then going though a series of command prompts and using DISKPART, something first detected the partition that had Windows 10, but I got an error at bootrec /fixboot ("Element not found"). I somehow restarted the computer booting to USB again and saw the operating system available ("Continue to Windows 10") and this time I was able to click "Repair" and it worked. Still, it's not good I don't know exactly what happened and how I fixed it.

Definitely boots now, but I still have one partition with free space and the other partition contains Windows 10. I don't know the correct way to merge the free space into the Windows 10 partition without making the same error that affects booting.

The unallocated partition is where I deleted Windows 7 install. How do I merge the free space with the Windows 10 partition, which now boots, without causing another boot error?

 

[USAFRet]

I think through a series of booting the USB Windows 10 Creation Tool, then going though a series of command prompts and using DISKPART, something first detected the partition that had Windows 10, but I got an error at bootrec /fixboot ("Element not found"). I somehow restarted the computer booting to USB again and saw the operating system available ("Continue to Windows 10") and this time I was able to click "Repair" and it worked. Still, it's not good I don't know exactly what happened and how I fixed it.

Definitely boots now, but I still have one partition with free space and the other partition contains Windows 10. I don't know the correct way to merge the free space into the Windows 10 partition without making the same error that affects booting.

Before you do ANYTHING ELSE, please show us a screencap of your current Disk Management window.
Upload your pic to imgur.com, post the link here.

 

[Petros_K]

Got it settled, though in a roundabout way.

Now that Windows 10 was booting again, and because I needed to backup this drive including files, folders, and applications before any other changes or mistakes were made, I cloned it to a spare hard drive. I used Disk Genius, which for Disk 2 you see in the screenshot above moved the unallocated space behind (to the right of) the partition with Windows 10.

After cloning it was now possible to go into Windows Disk Management and click on the Windows 10 partition and select "Extend volume..." to add the free space to the C partition, which is what I could not do initially.

I had thought because there was an OS on each partition (the unallocated space had been a Windows 7 partition), I could just delete the partition that had Windows 7 on it and I would still be able to boot given the other partition still had Windows 10. That was a mistake but I'm not sure why. Maybe it's where the boot MGR was stored?