In this howto there are the steps to follow when a Windows 10 OS is not bootable anymore and you haven’t a recovery disk. This is a typical case after a new OS will be installed on Dual boot or boot partition was altered.
- Download Windows 10 iso:
- Download the official Windows 10 image
- Prepare USB to be bootable:
- Open GParted with
Select the USB drive
Device > New partition table
Apply: this will delete any data on the USB
Create a new NTFS partition then Apply (do not use FAT32 since some files can be greater than 4GB)
- Unplug and plug USB
- Copy all Windows files to the empty USB drive using 7zip with:
7z x -y -o/media/user/path-to-USB/ Win10_1809Oct_Italian_x64.iso
- If something goes wrong during copy, you can mount the ISO image then rsync the source with the USB drive (the trailing slash is important):
rsync -avzp /media/myuser/CCCOMA_X64FRE_IT-IT_DV91/ .
Add boot flag
- Open GParted selecting the device just written
- Select the new partition then
- Select Partition > Manage flags
- Select boot flag (esp will be auto-selected)
- Use windows tools
- Follow this howto by MS to recover MBR, restore BCD or similar actions
You can follow these steps to write on a USB a recovery ISO from windows the same way.
- Windows Vista
- Ubuntu 9
- (on the same disk, different partitions)
Today I’ve to reinstall Windows. I’ve already an installation of GNU/Linux (Ubuntu) on the same disk. I have to worry? In the past, I had to say a big YES. And since I do a Windows reinstall every 2-3 years, this carry back something from previous times.
(Please skip this paragraph.)
When I was a little boy, the best processor I was dreaming was Pentium 133Mhz, PCs were assembled in my country and my days was filled with Duke Nukem 3d and Lucas Arts adventures, well in that days I had a freaking fear to lose all my precious savegames and BASIC experiments due to a disaster. I discovered a real MBR disaster several years later, with Mandrake and Windows 98.
Well, now things are easier.
- Backup your files from Windows (Lucas Arts adventures savegames too…).
- Reinstall that crappy OS that you had to have to play some games to the partition that it deserves.
- After the operation Your Master Boot Record is gone, GRUB is gone. Linux, where are you??
- Download Super Grub2 Disk.
- Take an old CD-RW (that one with the photos of your sister kitten that she loves so much), erase it and burn the bootable iso on it.
- Now follow the instruction from the website. I’ve followed these steps:
- Select Detect any OS. On the next window, select your GNU/Linux distribution, identified by the kernel version (the more recent version is usually the right).
- Now that your distro is successfully running (i.e. Ubuntu), you have to rebuild the Grub bootloader, putting it on the MBR of the disk.
- Open a shell and type:
Where /dev/sda is the device for the disk where the two OS are. If you have doubt, use tools like gparted to inspect your disk searching for the right device identifier.
- After restart, Grub is running again! So Windows is reinstalled without even touching Ubuntu.
If you’re also interested on changing grub boot sequence order, follow this howto.