Installing Windows in a secondary drive having EOS as main

Hello everyone,

I am very happy with EOS, I have it in my old laptop and it runs like a charm.
For work reasons I need to have Windows on a secondary drive (I don’t like VMs). I was expecting to be able to just install it on a brand new ssd (ATA KINGSTON SA400S3), but it seems like I was wrong. In the installation screen I get this:

windows could not create a new partition or locate an existing oney

Im using Rufus and Legacy BIOS (MBR).

I don’t really understand well how grub works, but I really don’t want to mess it up. I have been trying solutions from the internet, but only those that don’t mess with my other drives.

Does anyone have an insight on this?
One of the “solutions” talked about changing the SATA Mode from AHCI to IDE, but I didn’'t really felt like doing that, as I thought it may mess up something.

sudo efibootmgr -v
EFI variables are not supported on this system.
error trace:

sudo parted -l
Model: ATA KINGSTON SA400S3 (scsi)
Disk /dev/sda: 240GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags: 

Number  Start   End    Size   Type     File system  Flags
 1      1049kB  240GB  240GB  primary  ntfs         boot

Model: ATA WDC WD7500BPKX-2 (scsi)
Disk /dev/sdb: 750GB
Sector size (logical/physical): 512B/4096B
Partition Table: msdos
Disk Flags: 

Number  Start   End    Size   Type     File system  Flags
 1      1049kB  750GB  750GB  primary  ext4

Model: ATA TOSHIBA THNSNH12 (scsi)
Disk /dev/sdc: 128GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags: 

Number  Start   End    Size    Type     File system     Flags
 1      1049kB  119GB  119GB   primary  ext4            boot
 2      119GB   128GB  9449MB  primary  linux-swap(v1)  swap```

Thank you for your help and time,

How I would do it:
-Disable or remove the SSD with eos installed an install Windows clean an the new sdd
-enable or re-install the first ssd with eos an change in the bios the boot-order that the eos drive start first

probably you can’t chose windows on grub, to do that you need to enable os-prober

sudo nano /etc/default/grub

remove the # from #GRUB_DISABLE_OS_PROBER=false
exit nano (super+X) while saving the file
sudo grub-mkconfig -o /boot/grub/grub.cfg

now you should be able to boot windows from grub


Hello @arcDaniel ,
Thank you very much for your response.
I would love to try that but I believe the SSD where EOS is installed is a mSATA buried deep inside my laptop, it is not an easy one to take out unlike the other 2, I may look at disassemble my laptop nonetheless, although I’m a bit scared of disassembling the whole thing.

I could also look at creating an image of the ssd maybe and move it to the other ssd? and then install windows in the mSATA and leave the new, and better SSD for EOS?

Or is another way out?

Thanks again for your time :slight_smile:

Generally, I install windows first then eos second, that would be the ideal case if you can backup your eos data.

Perhaps you could boot into windows recovery or repair mode then wipe eos. Then windows takes over the booting process.

Then reinstall eos with grub on the other drive and enable os prober as mentioned above. Then grub takes over the boot process.

I like to point out that I only deal with UEFI and GPT partition scheme, not sure if there are any other quirks with using legacy and MBR to dual boot windows and Linux.

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There seems to be already a partition on the Kingston drive you want to install Windows on. Normally this shouldn’t be a problem but apparently Windows installer is unhappy with something.

Personally, in a scenario like yours, I would try the following:

  1. making sure to have a Live USB of the latest EnOS’ iso

  2. Using Gparted on the live ISO to wipe out the Kingston drive by creating a new partition table on it: msdos

  3. Backup my personal data from the EnOS drive. In case worst come to worst, you could always reinstall the OS and restore your data.

  4. Launch the windows installer and point it to the Kingston drive and install Windows. In principle, in MBR mode, it should write the bootloader to the mbr of the Kingston drive.

  5. In the (unlikely and) unfortunate event of the EnOS’ bootloader on the MBR of the EnOS’ drive being overwritten by Windows, you could use your Live EnOS usb to restore Grub’s bootloader.

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Hello @pebcak ,
Thank you for your response.

I have tried your steps, but I believe I am having the same issue. No matter how I format the ssd, be it from either live usb (windows or EOS) or from my current isntalled EOS, I get the same error.

I tried formating it as FAT32 (which made windows complaint) and NTFS.

When you say “msdos” do you mean the label of the partition? because GParted doesnt allow a “msdos” file system, I guess that’d be FAT32.

I also tried the mkfs.fat and mkfs.msdos.

I am now in the process suggested @Zircon34 ; installing EOS in my new drive and transferring everything to it, and maybe install Windows within the mSATA drive. I’m also considering VM at this point hehe.

Kind regards,

I mean partition table.
In Gparted >> Devices >> Create partition Table >> msdos

I suggested msdos since your EnOS install is already installed in MBR/Legacy mode on a disk with msdos partition table.

Now that you are going to build the whole thing up from scratch, if your system supports UEFI boot, I would suggest to have GPT (Guid Partition Table) on your disks.

Disable CSM/Legacy boot mode in BIOS and install both of your systems in UEFI mode.


Hello everyone,

In the end I found out that I could install windows as a GPT partition (without changing anything on my MBR EnOS), so I basically decided to use the Legacy BIOS/UEFI switch to change from EnOS to Windows, no the best solution but it will work for now, as in the future I will make my EnOS UEFI as well, as suggested by @pebcak.
I guess this is an OK temporary approach as long as I don’t mind changing this switch every time I want to change OS? I will be working mostly on EnOS and from time to time on Windows. Or do you guys think there are some caveats I am not considering to this approach?

In case anyone is interested:

1.- I first back up’d my EnOS.
2.- With a EnOS live USB I created a GPT partition on my new SSD.
3.- On a Windows device I created a Windows UEFI live USB with a portable version of Rufus.
4.- I changed my BIOS to start in UEFI mode.
5.- I installed Windows with no problems.

Thank you very much for your time :slight_smile:

EDIT: the key I had to press in order to access the boot menu changed in my laptop depending on whether I was on UEFI or Legacy. While in Legacy I had to press F2 during the startup whereas while in UEFI it was F12… In case someone is banging his/her head against the keyboard like I did wondering why the hell I couldn’t access the boot menu when in UEFI…


To me having mixed disks GPT/MBR and UEFI/Legacy on the same system sounds like a recipe for disaster. I would avoid that on my system. I would rather follow @pebcak advice to install all in UEFI…

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Thank you @Zircon34 for your input. I think you are right, I have edited my last reply marked as solution for now so that it reflects that changing the UEFI/Legacy for the sake of changing the OS is not a great approach, but it works as a temporary solution. During Christmas I will face work on moving EnOS to UEFI.

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