Adding Windows 10 dual-boot (clean install) to a Windows 7 Laptop.

Now that we have the ability to clean install 10 onto a pre-existing 7 machine, and then activate using the pre-existing 7 key...

1. Created a 200GB partition for 10.
2. Booted from USB 10 installer (created today, so latest version).
3. Installed 10 into said 200GB partition with no reported errors.
4. Installer first reboot re-loaded the installer, so removed and rebooted. You'd think they would do something about this, but I'm not holding my breath. Also few walkthrus mention this fact.
5. Boots Windows 7 original bootloader with no sign of the 10 install, so unable to continue on with the setup.
6. Booted into 7 and I can see the installed 10 partition (with no drive letter obviously). Assigned a drive letter and explorer shows Win 10 files are present, and what looks like a bootloader.

According to various sources a Win 10 install will lay down its own bootloader and provide a dual-boot to the pre-existing o/s, in this case Win 7.

As a quick and dirty I used EasyBCD to create a third entry to 10 inside the 7 bootloader, but it throws an error when trying to use that option, something about not being able to verify the o/s.

It should be noted this is an MBR arrangement, a Dell machine, with a separate 20GB OEM recovery partition containing the Win 7 bootloader.

Any "intelligent" ideas much appreciated.

From an elevated ("Run as administrator") command prompt in Windows 7 try:

bcdboot e:\Windows

The path in red will be the path to the Windows 10 "Windows" folder.

Check if the boot timeout option defaulted to 0.

NavyLCDR said:

From an elevated ("Run as administrator") command prompt in Windows 7 try:

bcdboot e:\Windows

The path in red will be the path to the Windows 10 "Windows" folder.

I asked for an intelligent response and you not only gave me that, you also fixed the problem.

After running your solution and restarting, the machine booted directly into the Win10 bootloader, offering me Win10, plus my original two options from my Win7 bootloader.

Thank you very much.

I've yet to try Win7, but I've been able to enter Win10, update and active it (with a Win7 product key).

It's a shame the problem exists in the first place of course. This will be the 4th Win 10 install on different machines, and all four had varying problems. One of which requires a new WiFi card to resolve.

cereberus said:

If NavyLCDR's method does not work (usually does of course), you could try this.

Create a bootable Winpe Rescue drive usb stick or dvd using this link :-

Windows 10 Recovery Tools - Bootable Rescue Disk - Windows 10 Forums

copying iso files using rufus or diskpart commands.

Boot from drive, and run Macrium Reflect.

Then select restore tab, select 'fix windows boot problems'.

You should see Windows 10 and Windows 7 listed.

Then click next, finish and it will recreate the dual boot menu for you.

Worth creating that Winpe Rescue Drive anyway as a lot of great stuff on it, and has bcdedit on it, amongst other good stuff.

NavyLCDR's solution did work, but many thanks for the information.

My second bootloader option is Macrium Reflect's utility I backed up various partitions with it, just to be on the safe side.

Edwin said:

Check if the boot timeout option defaulted to 0.

Thank you for the reply, but NavyLCDR's solution worked.