Installing Windows 7 and 8.1 on the same system

So many people complicate Windows 8.x/Windows 7 installs. This nonsense of unplugging one drive, installing OS via bootable media, then plugging back in original drive; downloading some bcd software to add boot entry...
You just need 1 GUI tool(Disk Management) and 2 CLI tools(DISM, BCDBoot)

Really, best way to dual boot Win8/Win7 on a machine that has Win8/8.1 is to do the install all inside of Windows 8.

In diskmgmt.msc, shrink HDD down to size you want your Windows partition, or if installing on another HDD, format that HDD as NTFS.

Then put in your Windows 7 media into Optical Drive.
Then manually install Windows, thusly:

Assuming: C: is OS partition, D: is OS2 Partition, and E: is Optical drive with Win7 disk.

Open admin level CMD prompt and type: DISM /apply-image /imagefile:E:\sources\install.wim /index:2 /applydir:
allow that to complete, you'll get a progress bar; after it says completed, type BCDBOOT D:\windows /d, and you'll get "Boot files successfully created".

after that, restart PC and you should be two boot entries, Windows 8.1/Windows 7 and just select what you want to boot too; in msconfig in either install you can select which you want to be default.


Edit: Have to add, the /index switch in the DISM, you'd want to change that depending on the version of Windows you are activating. For x64 install (which is the only one that'll install in UEFI mode that Win8 would come with), is usually: 1: HomeBasic, 2: HomePremium, 3: Professional 4: Ultimate.
x86 is usually: 1: Starter, 2: HomeBasic, 3: HomePremium: 4: Professional
But you'd want to verify that with DISM /get-wiminfo /wimfile:E\sources\install.wim

The installer has configured a Dual Boot since Vista. We no longer use XP methods because of automation.

We also do not install an OS from within another because that locks out the C letter so that it isn't available for the new OS. But when installed from boot any multi-booted OS when it starts will see itself as C.

Had you been here since the earliest days of beta you would have witnessed these evolutions in how things are done, an exciting ride which led to these becoming the top tech forums in history. Believe me all of the changes were questioned and tested, weighed against all other options old and new, in tens of thousands of cases over the entire run of Win7.

Stick around as we continue to evolve. Show us your ideas in practice and if they are better then they will catch on. Nobody here has a closed mind.

gregrocker said:

We also do not install an OS from within another because that locks out the C letter so that it isn't available for the new OS. But when installed from boot any multi-booted OS when it starts will see itself as C.

C: will not be locked by the 2nd OS, that is what the /d flag in BCDBoot is for. /d preserves current boot entry, and adds the Windows install as a dual boot

bcdboot /d Specifies that the existing default windows boot entry should be preserved.

The 2nd OS will have C: has OS partition, and another drive letter will be assigned the the first installed OS.
If you don't use /d, then yes; your install will fail because that OS will be assigned letter D: or E: or some other letter and Windows doesn't like drive letter NOT on C:



I see no reason to unplug/install OS, then plug back in drive and mess with 3rd party BCDEdit utils; or even booting to install media and running the standard setup process to dual boot.
Being able to manually install 2nd OS inside a working OS so you can do other things makes more sense to me.

It's all preference on how it is done; I would be annoyed by the dual EFI partitions the OP has, but probably doesn't bother most folks.

Just want to note that it most certainly can be done without the issues you describe in above quoted.

We've seen literally thousands of cases of the boot manager being derailed to another hard drive when it wasn't unplugged during install. The installer will place the boot files on the first Primary partition in order. The only way to avoid this is to have the target HD in DISK0, or see that any preceding partition is Logical which cannot receive boot files.

But as you can see this isn't easy to explain, so instead what's worked easiest is unplugging the other drive. This keeps them independently bootable as well, while having them configured into a Windows Dual Boot requires surgery to remove the one which isn't marked System Active. When unplugged each can boot itself, then if a BIOS Boot is not desired one can add the other to a Windows Boot Menu easily with EasyBCD (again, automation) while they remain independently bootable - the best of all possible outcomes.

The commands you would issue are given after this is already done. The C letter can no longer be issued without ruining the install, by any method we've ever seen here.

I apologize for having disappeared for such a long time. I've been using Windows 7 primarily with WMC and didn't try to boot it in Windows 8.1 until yesterday to patch it up and prepare for upgrade to Windows 10. I could only boot from Windows 8.1 by unplugging my Windows 7 drive. After installing all the patches for Windows 8.1, I shut the machine down and plugged the Windows 7 SSD before turning it on. It still wanted to boot from Windows 8.1 so I unplugged the HDD and it booted from Windows 7. Plugged in the HDD after that and the machines went through some FDISK activity and now it boots from Windows 7 SSD. I had to restore Windows 7 to a restore point to fix some corruption and then started running recovery on Windows 7 but cancelled it during the initial phase. During recovery, the system seemed to be aware of both OS'es on the two drives.
If I run the recovery to repair installation of Windows 7, will it start giving me options to boot (from F12) or will it mess up my system in any way? I'm asking this question because I don't understand UEFI as well.
Thoughts, ideas?

What Recovery are you referring to? Recovery here means Factory Recovery to shipped condition, or Image Recovery using a System Image.

Compare the 7 install you have to the perfect one compiled in link beneath surf picture below. If it doesn't compare I'd go to the perfect install to enjoy best performance.

Did you ever add 7 to a Dual Boot menu using EasyBCD from 8 as suggested since your BIOS menu doesn't offer choice of hard drives? In this case the HD priority is a different setting.

Once 7 is bootable you can also Upgrade 8 to 10 with both drives plugged in and the installer should configure a Dual Boot. One may not be independently bootable then however, another reason to install with only one HD plugged in so all are independently bootable, then add secondary HD OS from Primary using EasyBCD which leaves each independently bootable, whereas the Windows installer only keeps the Primary self booting.

gregrocker said:

What Recovery are you referring to? Recovery here means Factory Recovery to shipped condition, or Image Recovery using a System Image.

Did you ever add 7 to a Dual Boot menu using EasyBCD from 8 as suggested since your BIOS menu doesn't offer choice of hard drives? In this case the HD priority is a different setting.

Perhaps I used incorrect terminology. I started Windows 7 reinstall process which saw both disk drives with their own operating systems. I cancelled it at that stage and the system booted to the existing Windows 7 installation.
To boot from Windows 8.1 and install BCD, I would have to disconnect the Windows 7 disk. Will BCD recognize it if I connect it afterwards? I just don't want to lose the ability to boot from Windows 7 and run WMC. Not understanding UEFI, I don't want to set it up in a way that I cannot return to my current setup where each OS is installed individually on its own drive.

Thank you for your patience. Granted that my Disk Mgmt is a mess but I can only take credit for two actions in creating it:
1- Unplugged the 1TB HDD that came from the factory Windows 8.1 installed with all the partitions. I then plugged in a new SSD and installed Windows 7 on it before reconnecting the original HDD.
2- Created a partition on the HDD to store my WMC Media. I have no idea why there are three Recovery partitions on it.
I plan to upgrade from 8.1 to 10 once I have found a good replacement for WMC. In the meantime I'd like to be able to dual boot to test the WMC alternatives on 8.1. What's preferable in this instance- installing EasyBCD on Windows 7 or 8.1?