How to install Windows 10 WITHOUT converting to GPT?

[Achint2000]

Will need experienced help with this.
It's a long explanation, brace yourself.
Written in points to be more clear.
If needed, see my build specs by clicking on my profile pic.

This is how I got Windows 7 and Windows 10 to dual boot on the same SSD's different partitions WITHOUT converting it into GPT.... About 3-4 months ago:

Spoiler

1. Had Win7 on 256GB MBR SSD, tried to convert to GPT using gptgen as I wanted to install win10 clean but Win10 clean install from boot doesnt install on MBR.

2. After gptgen completed, a BSOD came, my win7 stopped booting.

3. Trying to recover, accidentally executed "clean" in DISKPART. Entire drive was unallocated.

4. Used EaseUS Partition Recovery (Boot version) to recover but it was recovered as a MBR disk, with the previous 2 partitions: ((System Reserved and Windows 7 drive)), and the empty partition recognized as a normal logical disk.

5. My Windows 7 booted successfully after somehow repairing boot files from the Win7 Setup disk.

6. Then, instead of clean installing Win10, I installed another copy of same Win7 from the same setup CD to the logical partition of the same SSD and upgraded it to Windows 10 Pro x64 from running the setup from the iso file in Win7 Environment. Everything worked perfectly fine and normal.

7. Ended up with a successful Windows 7 and Windows 10 Dual Boot on the same SSD, without converting it to GPT. (yay)

8. Knew it's messed up, avoided chkdsk at all times, cancelled all scans.

How chkdsk screwed up the logical drive partition and Windows 10, Win10 won't start. After a few months from getting a proper dual boot:

Spoiler

1. Power cut one day while Win10 was booting, unsuccessful shutdown. (The power cut timing was too perfect, as Win10 on my SSD takes like less than 5 seconds to load, and it turned off exactly in those 5 seconds)

2. After the power cut, always booted from Win7 as I use it as the primary OS.

3. Booted Win10 3 days ago, it launched automatic repair without even prompting.

4. It "scanned for disk errors" and suddenly restarted, then showed a message "automatic repair cannot repair this comp" or something.

5. About 30GB Data from that partition, videos, game files, pics, movies, even windows's own registry had it's size "0 bytes".

6. Successfully removed and completely formatted Windows 10 partition.

7. Scanned my Win7 partition, no drive errors found by chkdsk. Win7 boots all fine. Everything must be ok.

Note: I barely have any free space, and absolutely no backups of a total of 5 TB Data (3x 1TB External HDDs, 2x 1TB Internal HDDs, 1x 256GB Internal SSD)

1. How do I reinstall Windows 10 in a new partition (not logical partition/drive), on the same SSD?

2. Can I do that without having absolutely ANY effect on my current Windows 7 installation? (Like the drive letters n everything should remain the same, changes to boot menu are ok and obvious.)

3. To dual boot, Can I install another copy of Windows 7 on the new partition and properly upgrade it to Windows 10?

4. Will it function just like before? (I know my files/settings won't be there)
5. If yes, how can Windows 10 be upgraded from Windows 7, still being on a MBR disk?
6. Will chkdsk still create issues like before if I do this? Why/why not?
7. If chkdsk will create issues, how do I completely prevent it from scanning the drive? (Can I rename the extension of chkdsk.exe in system files so it won't work?)

Thanks for any help in advance

 

[SkyNetRising]

1. How do I reinstall Windows 10 in a new partition (not logical partition/drive), on the same SSD?

Boot from windows installation media, create partition, install.

2. Can I do that without having absolutely ANY effect on my current Windows 7 installation? (Like the drive letters n everything should remain the same, changes to boot menu are ok and obvious.)

Sure. It should not affect windows 7 in any way.

3. To dual boot, Can I install another copy of Windows 7 on the new partition and properly upgrade it to Windows 10?

Sure. You can do it that way too.

4. Will it function just like before? (I know my files/settings won't be there)

If everything is done right, everything should be ok.

5. If yes, how can Windows 10 be upgraded from Windows 7, still being on a MBR disk?

Windows 10 can be installed in UEFI mode as well as in legacy mode. There are no problems either way.

6. Will chkdsk still create issues like before if I do this? Why/why not?

Chkdsk runs only, when volume is labeled dirty (it means - there is some file system corruption). No corruption - no chkdsk.

7. If chkdsk will create issues, how do I completely prevent it from scanning the drive? (Can I rename the extension of chkdsk.exe in system files so it won't work?)

Just let chkdsk run and fix, what it can.

 

[mbarnes86]

Hi

Is windows 7 working ?
If so a picture of disk management screen would be usefull

I have xp then 7 then 10 on a 240 GB SSD each in a primary partition and installed in that order. MBR partitioning is ok upto 2 TB though GPT has advantages of a backup partition containing partition information


The win 10 boot manager over writes the win 7 boot manager if win 10 is shut down but not if win 10 is rebooted

Personally i would disconnect the internal hard drives before doing a re install or repair to ensure no boot manager partitions are on the hard disks instead of the SSD

I dont see any reason to install win 7 then upgrade to 10 unless using a oem windows 7 with manufacturers drivers and utilities you want to keep under win 10


Cant say more without seeing your disk management screen for the SSD?

I expect a boot manager partition at front of SSD, then one or more primary partitions for win 7 & 10

A repair install of 10 over the old 10 may work though probably needs a format as part of process

I would look for SSD manufacturers diagnostics to test SSD before anything else to save wasting time if SSD is broken as i would not expect chkdsk to cause serious problems on a disk in good condition

Regards
Mike Barnes

 

[Achint2000]

I still don't get it. How can Windows 10 be installed on upgrading Windows 7 still being on an MBR disk?

And if it can use some legacy mode to install, why doesn't it give an option for that when it's being installed from boot media?
I get the message saying windows 10 can't be installed on an MBR disk.

I shouldn't be getting any drive errors now, as I deleted the volume itself, formatted it twice and ran chkdsk on both partitions. Can't "scan for drive errors" on the system reserved partition though.

 

[SkyNetRising]

And if it can use some legacy mode to install, why doesn't it give an option for that when it's being installed from boot media?

To install OS in legacy mode, you have to boot in legacy mode.

If you boot in UEFI mode, legacy mode install is not available and you have to install on GPT disk;
If you boot in legacy mode, UEFI install mode is not available and you have to install on MBR disk.

Your OS installation media might be prepared for installation in UEFI mode only.
You can use rufus to prepare USB installation media for either mode.

 

[mbarnes86]

Hi

Have you changed any bios or uefi modes relating to legacy or uefi (gpt) disk access?
Changing this setting may break win 7 startup

Windows vista SP 1 and 7 , 8 and 10 all support gpt partitioning if uefi bios setup correctly and 64 bit windows used

Or mbr partitioning in legacy mode and boot disk size not exceeding 2 TB
32 or 64 bit windows

Regards
Mike Barnes

 

[Achint2000]

How can I boot in legacy mode? I have an ASUS Strix z270F motherboard.

I don't currently have a USB, so I'll be partitioning about 8GB from one of my external HDDs and using that to boot. Is all this ok?

 

[Achint2000]

Hi

Have you changed any bios or uefi modes relating to legacy or uefi (gpt) disk access?
Changing this setting may break win 7 startup

Windows vista SP 1 and 7 , 8 and 10 all support gpt partitioning if uefi bios setup correctly and 64 bit windows used

Or mbr partitioning in legacy mode and boot disk size not exceeding 2 TB
32 or 64 bit windows

Regards
Mike Barnes

Resetting BIOS is a usual thing for me as I overclock frequently, and sometimes touch the reset BIOS jumper cap with the screwdriver I'm using to start the system (shorting out power buttons. I dont have a case)

My Windows 7 boots perfectly fine, though I'll still have to check if it's set to UEFI or Legacy in BIOS. I remember being able to boot from both of the settings though.

Didn't refresh so didn't see new answers. Here's a screenshot of diskmgmt.msc: https://i.imgur.com/i2FQ6dg.png

I installed Win7 first, then Win10 over it because Win10 would always say that it cant be installed because the partition is MBR, not GPT. So, that was the only way I knew.

 

[mbarnes86]

Hi

I cant read the writing in the disk management screen but with only 3 partitions and two with windows (only one is hidden ) that indicates mbr partitioning

Is uefi disk access set to legacy? ( mbr)
Putting win 7 in 3rd partition after windows 7, in 2nd partition followed by running second win 7 (if you can tell which one is the second one from the boot menu entry)

Then running win 10 upgrade from 7 does not do any harm but wastes time

A proper windows 10 boot usb disk should be on a fat 32 formatted memory stick disk and when created using the Microsoft utility will wipe out any info on the usb hard drive or memory stick

One user was not expecting all his data on his external usb hard disk to be erased when a bootable windows 10 iso was installed on it.

Regards
Mike Barnes

 

[SkyNetRising]

How can I boot in legacy mode?

You're already booting in legacy mode. Your current OS is installed in legacy mode. Just disable UEFI boot in BIOS so it doesn't give you UEFI boot options.

I don't currently have a USB, so I'll be partitioning about 8GB from one of my external HDDs and using that to boot. Is all this ok?

Isn't your external hdd USB connected? When rufus creates USB install media, drive gets repartitioned and formatted. You'll loose all data on that external drive.

 

[Achint2000]

Writing in disk management points to unallocated space saying "will format this" and says "for windows 10".

I still dont know if its set to UEFI or legacy as i didnt goto bios yet, and i reboot very less frequently. I'll update as soon as possible.

@SkyNetRising, I did it about 4-5 months ago, using some other USB-DVD tool, I dont exactly remember because I was up all night and barely slept (summer vacations). Shortly after attempting and failing to install win10, as im always low on space, I ended up deleting the partition and extending the normal partition. I have no idea why I didn't lose any data.

I had it in whatever mode my BIOS is, which booted both Windows 7 and Windows 10 on the same SSD, so I have no idea.
Again, will update ASAP, it's 1:30 AM. Appreciating all the help.

 

[Achint2000]

Ok, I finally took out some time and restarted into the BIOS. Here's what I saw:

And just to be on the safe side, I'll get a USB drive soon enough to install Win10.
What exactly do I have to do in the BIOS?

Also, as I currently have a Win7 installed, does it boot in UEFI or Legacy?
If I install Win10 in dual boot, which one will it boot?

 

[SkyNetRising]

Told already - your current OS is installed in legacy mode (MBR disk partitioning).

Change Boot device control setting in BIOS to Legacy only - and you will no longer have any UEFI boot options.

All OS on same computer have to be installed in same mode - either all in UEFI or all in legacy mode
(well you could install on one drive in UEFI, on other drive in legacy, but you'd need to change BIOS settings each time to switch between them).

 

[Colif]

UEFI boot can boot MBR drives, you don't have to switch between them at boot up. If an MBR hdd is present when Win 10 is installed, it will add the details of that drive to the windows boot manager. MBR can't boot GPT though.

That only applies to multiple drives though, Win 10 will refuse to install on MBR unless you change it to Legacy as suggested. It only acts like this on fresh installs, Win 10 happily run as MBR on an upgrade.

 

[Achint2000]

I finally got a 32GB USB. Formatted it to NTFS. Downloaded a Windows 10 iso from the official site.

Is this all I have to do on rufus?

 

[SkyNetRising]

For installation in legacy/csm mode - yes. Those are right settings.