Safe to format HD w separate Dual Boot OS?

[upsidedownjim]

I have a dual boot setup with one OS (Windows 8) installed on a separate hard drive from my main OS (Windows 10) and would like to format the hard drive with Windows 8 on it since I'm not using it.Is it safe to do so from within Windows 10 > Disk Management > Format?

Hard Drive 1 - Primary Boot Drive (Windows 10)
Hard Drive 2 - Partition 1 - Windows 8 ; Partition 2 - regular data partition.

When I boot up I don't see a boot manager to choose between Windows 10 or WIndows 8. I'm a bit paranoid if I format the drive with Windows 8 from within Windows 10 something will screw up.

Would the following procedure be safe to use:

https://www.sevenforums.com/tutorials/210983-dual-boot-delete-os.html

Thanks!

 

[Colif]

can you show us a screen shot of disk management? (upload picture to imgur and share link)

using a method off 7 forums for a dual boot between win 8 & 10 would probably be wrong, they use different boot formats

 

[upsidedownjim]

Thanks for the reply - here's a photo of the disk management screen:

 

[Colif]

Glad I asked. If you wipe your win 8 drive then win 10 won't boot.

Reason being the 100mb EFI partition on Disk 1 is the boot partition for disk 3 as well. This happens if you have the win 8 hdd in PC when you install win 10, it sees the EFI partition and uses it for win 10 as well.

What you will need to do is create an EFI partition on disk 3 if you format disk 1. Have a look at Option 1 in Genet's post here: https://www.eightforums.com/general-support/52515-windows-8-cant-start-due-missing-efi-partition.html (instructions work for Win 10, you will need an installer so if you don't have one, download the Windows 10 media creation tool and use it to make a win 10 installer on USB)

I would d/c all other drives except C when you remake the efi though I think its pretty safe to leave them there if you find right drive when doing commands (it would just make it easier to find right drive)

 

[upsidedownjim]

I'm glad you asked, too! Thanks!! Also, thanks for finding the link for Genet's instructions. Much appreciated!

Just for clarification and my understanding - why would I use Genet's option 1?

- Option One: How to create the missing EFI System partition, if you still have the unallocated space available for the EFI System partition and no other unallocated space on the drive.

Am I looking at unallocated space on disk 3 (Windows 10) or disk 1 (Win 8 with the EFI System partition)? My reading of disk 3 is that I don't have unallocated space on it, so I should use Genet's Option 3 to shrink the Windows OS partition to fit the EFI boot partition?

- Option Two[: How to create the missing EFI System partition, if you have the unallocated space available for the EFI System partition.

This limits the EFI partition size if you have more unallocated space than needed, correct?

- Option Three: How to create the missing EFI System partition, if you do NOT have the unallocated space available for the EFI System partition.

This will, within the Windows OS Partition (C: ) shrink the partition size to fit the EFI partition.

So, the steps I should take are:

- Backup Disk 3 and any data on Disk 1 that I would need.
- Download Windows 10 installer to USB
- Disconnect all drives except Disk 3
- Follow Genet's instructions to create an EFI partition on Disk 3 to boot Windows 10 (confirmed option 1 or 3?)
- Re-Connect drives (or just disk 1 to avoid confusion)
- Format Disk 1 - can this be done within Windows or should I do this after booting the computer and before logging into Windows? Would the EFI on Disk 1 confuse booting into Windows with the newly created Windows 10 boot on Disk 3.
- Re-connect drives if I haven't done so already.
- Live happily ever after.

Thanks for you help! I would, definitely, have mucked things up without it.

 

[Colif]

Yes, option 3. Sorry about that, I was half asleep when I answered your question last night and only answered it when I did as you were around. I must have read the options wrong

I am pretty sure win 10 won't let you format disc 1 with windows 8 on it as it is like that, it would see a windows install and balk at the idea. Easiest way to format it is as follows

Downlaod Dban and burn it onto a USB
unplug PC
d/c all drives from PC except the win 8 install
boot up dban and wipe the hdd
unplug PC again and reattach the other hdds
format drive as you see fit in disk management

 

[upsidedownjim]

No worries! Appreciate you taking the time to help out!

So, I tried a couple things:

1. Disconnect all drives except for the drive with Windows 10. In doing this I was able to boot into Windows 10 with and without the 'Windows 10 installer' (I burned to DVD but assume USB would be the same).

2. Disconnect all drives except for the drive with Windows 8. I was unable to boot. Got a message: Reboot and Select proper Boot device or insert Boot Media in selected Boot device.

So, how am I able to boot into Windows 10 if the boot partition is on the Windows 8 drive?

In my first post, in an effort to keep it concise, I left out a bit more of the OS history, which might be relevant (not sure):

A while ago I had Windows 7 and 8 dual booting onto one hard drive. Later on I purchased a SSD drive and wanted to install Windows 7 on that. Due to the limited space of the SSD I tried to dual boot with Windows 8 on the old hard drive. I don't remember exactly what I did but don't recall the dual boot working after that attempt. At that point I didn't feel like trying to troubleshoot what went wrong, so I left things as they were and just used Windows 7. I then upgraded Windows 7 to Windows 10 shortly before the free-upgrade offer was set to expire. So, that's where I'm at now.

Long story short, since I was able to boot into Windows 10 without the Windows 8 drive (containing EFI partition) connected:

- Can I safely format the Windows 8 drive?
- Could that be done within Windows or just after booting up the computer (booting off Windows 10 installer)
- Would I still need to shrink the Windows 10 drive to create a EFI partition?

I tried shrinking the volume following Genet's option 3 and also in disk management in Windows 10 ("Shrink Volume") - neither option worked as I got an alert saying there wasn't enough space. I was trying to shrink to 260 mb.

Sorry for the lack of info led us down the wrong path! Thought it would complicate things too much if simpler steps worked.

 

[Colif]

lol. now you tell me...

I will give a little background. Win 7 & every other version of windows before it used an MBR partition format, Win 8 & 10 use GPT. If you upgrade a PC from 7 to 10 it keeps the MBR format but if you fresh install win 10 on a system that supports GPT it will insist on a full format off hdd and create GPT partitions
MBR systems use the MBR partition to boot from, GPT systems use the EFI

http://www.howtogeek.com/193669/whats-the-difference-between-gpt-and-mbr-when-partitioning-a-drive/

Okay, win 10 is running off an MBR partiton type, it can boot by itself as you can see. I should have asked if it was a fresh install or a Upgrade. I just saw the EFI partition and assumed I knew what had happened

1. Yes, you can safely format the win 8 drive
2. I think you might be able to use this to clean the drive from within windows - http://knowledge.seagate.com/articles/en_US/FAQ/005929en just be careful to clean right drive.
You can also do that off the win 10 installer if you want to play it safe and remove all other drives from power so as to avoid accidentally deleting wrong drive
boot from installer, on 2nd screen after languages, choose repair this PC, not install
choose troubleshoot
choose advanced
choose command prompt and do the clean


3. no, its not needed for your current build.

 

[Colif]

If you ever fresh install win 10 on the hdd it will want to wipe it,. so just remember that for future

It will create the EFI partition when it needs one.

 

[upsidedownjim]

Oh man! I wish I had mentioned that off the top! On the plus side I definitely have a fuller understanding of the situation and the various options. I tried finding a solution a few times over the past year or two but couldn't find a post or blog that addressed this scenario (not to say it isn't out there). Hopefully this will help others, as well. Thanks again for your time, knowledge and patience! Really do appreciate it.

I've formatted the drive and initialized as a GPT (not MBR) all looks good! Great info on the win 10 fresh install - I was thinking of trying that at some point.

Thanks again!!

 

[Colif]

Maybe, I wasn't very awake when i answered last night so i might still had jumped to wrong conclusion

 

[upsidedownjim]

Maybe, I wasn't very awake when i answered last night so i might still had jumped to wrong conclusion

lol - well, one way or the other you helped me get this issue resolved. Thanks again!