Windows 11 Pro 25H2 (insider preview) free upgrade installation on officially-unsupported outdated PC

[dualazmak]

Note and warning:
The Windows 25H2 upgrade installation procedure shared in this post is just for your reference; if you would like to apply this to your PCs, do it with your own responsibility and risks.

Important edit on October 1, 2025:
As of today October 1, Microsoft officially and generally released Windows 11 25H2.
https://www.windowscentral.com/micr...wnload-all-28-languages-here-for-x64-or-arm64
I could confirm that the "setup.exe /product server" command is still supported in the official/general release.
See, my post #40.

Edit:
please visit my post #29 for the upgrading summary as of September 18, 2025
-present summary (as of September 18, 2025), by the "setup.exe /product server" method shared in my top post #1; I could so far successfully upgrade to Windows 11 Pro 25H2 (from Pro 24H2) on the nine (9) officially "unsupported" PCs and PC-workstations


Now that Microsoft officially announced Windows 11 25H2 installation .iso image files under "Windows 11 Insider Preview (release Preview Channel) - Build 26200" link at their Insider Preview site, I just tested the free upgrade installation on Windows 11 Pro 24H2 running in rather outdated, officially unsupported, PC.

I know much info that this Insider Preview 25H2 is almost identical (or completely identical?) to the coming publicly-official 25H2 to be available very soon, hopefully by the end of September.

I could easily get/download "Windows11_InsiderPreview_Client_x64ja-ap_26200.iso" (Japanese language installer .iso in my case) from the Insider Preview site, mount the .iso image to a virtual DVD drive (Virtual Clone CD/DVD in my case), then I extracted/copied all the files and folders within the .iso image into one specific folder on my data HDD drive D: just under the root.

Just same as I wrote here, in the installer-package folder, the command with administrator rights "setup.exe /product server" is still alive and valid in the 25H2 installer package; using this command I could smoothly upgrade one of my outdated PCs running 24H2 to 25H2, with all the user settings applications desktop-icons desktop-background-image various-data/parameters etc. have been completely preserved/unchanged.

Edit:
Windows account and Windows product key, as well as Windows license status (active), are also automatically preserved/inherited to 25H2 by this "setup.exe /product server" upgrading procedure.

We will see the sign of "Windows Server is now being installed" during the upgrade procedure, but you may just ignore it; it actually installs 25H2 Pro (or 25H2 Home).

After the successful upgrade installation of 25H2, I manually applied all the available Windows Updates (as of September 13 Japan Time), then I confirmed the Windows version by "winver" command which tells that the present version is 25H2 (OS Build 26200.6584), with no problem at all, so far.

I believe we can apply this procedure for Windows 11 Home PCs, too.

M/B: MSI ZH77A-G43 _chipset Intel H77 (Panther Point Base)
CPU: Intel Core i7-3770 (Ivy Bridge DT)
MEM: 16 GB
OS-SSD: 128 GB
GPU: CPU incorporated Intel HD Graphics 4000

 

[boxerfan88]

Woo hoo!! No need TPM??

Yummylicious!!

 

[dualazmak]

Woo hoo!! No need TPM??

Yummylicious!!

Yes...
By this procedure, you can bypass all of the TPM check, CPU check, RAM check, and SecureBoot check!

 

[Snarfie]

I used Rufus.ie to upgrade my old 1TB HDD from Windows 10 to 11, and it worked flawlessly. It skipped the TPM and CPU checks, plus all the annoying setup stuff like forcing a Microsoft account.

For now, I’m still running Windows 10 with no problems on my new 2TB SSD it’s fast as lightning. When the time comes, I already know what to do.

Rufus - Create bootable USB drives the easy way

Rufus: Create bootable USB drives the easy way

rufus.ie

 

[dualazmak]

I used Rufus.ie to upgrade my old 1TB HDD from Windows 10 to 11,
.....

Yes, but I know you need to prepare installer USB memory of FAT32 format for Rufus.ie, right?

I also know that some of other GUI-based upgrade tool/applications (edit: including Flyoobe, Flyby11) are available for free "bypass installation" of 25H2, but I heard that they would just run "setup.exe /product server" in their background...

 

[Snarfie]

Yes, but I know you need to prepare installer USB memory of FAT32 format for Rufus/ie, right?

I also know that some of other GUI-based upgrade tool/applications are available for free "bypass installation" of 25H2, but I heard that they would just run "setup.exe /product server" in their background...

What i did is the following:

Yes you do need a atleast 8 gb USB stick an download the installer than i placed the downloaded windows 11 installation version an installer ony my old HDD ( which is USB connected to my new Windows 10 running SSD).
Than i changed the new SSD on my laptop for the old HDD with the USB installer an downloaded windows 11 version.

From there on it is quite easy. My old Windows 10 is starting up with windows 10. From there on install the USB installer execute it an follow the questions as you could see find in Rufus.ie.

Ps: copy your windows 10 licence code it will ask for that but it is not necessary to fill in.

Do know it is all on your own risk thats why i used my mirror old HDD. Atleast copy all neccecary data first from your HDD.

 

[dualazmak]

Of course, I have carefully backup-ed whole the Windows 24H2 MBR-SSD drive into a .vhdx file (virtual size-variable hard-disk-image-file prepared by Windows Disk Manager), before upgrading it to 25H2, using Paragon Partition Manager 14 15 Professional (very stable and reliable).
Edit: I essentially do not fully trust Microsoft's (Windows') role-back features/tools to former version of Windows OS prior to the upgrade.

And I always keep the Windows Product keys in my paper notebook and digital text files.

By the way, the above "Setup.exe /product server" upgrading procedure automatically securely preserves/inherits the Windows product key and Windows account, as well as Windows license approval status (active), to 25H2 with no problem at all.

 

[Monster]

Will this method still work for a PC that doesn't have a UEFI BIOS and so has a MBR hard disk?

 

[dualazmak]

Will this method still work for a PC that doesn't have a UEFI BIOS and so has a MBR hard disk?

This method is independent from BIOS and MBR boot sequence.

I assume/believe, therefore, it shall work, but I highly recommend you preparing "whole/complete backup disk copy" of your target OS MBR HDD (or MBR SSD) prior to try this method.

In my case, as shared in my above post #7, I periodically backup my MBR-OS-SSD-disk into .vhdx virtual disk image file (in other large data HDD) using Paragon Partition Manager 14 Professional; with the backup .vhdx disk image, if needed, I can very easily role-back the MBR-OS-disk using Paragon Partition Manager 14 Professional.

 

[dualazmak]

This method may not successfully complete if the target old Windows has the rare case of multiple bootable sequences/partitions.

In such a rare case, prior to apply this method, you need to make it to "only single bootable partition" by using "msconfig" - "boot" - "select present OS boot partition", and delete other bootable indicators/directors.

 

[Monster]

This method is independent from BIOS and MBR boot sequence.

I assume/believe, therefore, it shall work, but I highly recommend you preparing "whole/complete backup disk copy" of your target OS MBR HDD (or MBR SSD) prior to try this method.

In my case, as shared in my above post #7, I periodically backup my MBR-OS-SSD-disk into .vhdx virtual disk image file (in other large data HDD) using Paragon Partition Manager 14 Professional; with the backup .vhdx disk image, if needed, I can very easily role-back the MBR-OS-disk using Paragon Partition Manager 14 Professional.

Thanks for the quick response.

My intention is to clone my current system disk and remove it. Then attempt the 'upgrade' to Windows 11 using the cloned disk installed in the computer. That way I can revert to the original Win 10 system in a few minutes, just by swapping the disks back.

I also make regular disk image backups using Macrium Reflect, so it's a bit of a 'belt and braces' approach for me.

 

[Monster]

This method may not successfully complete if the target old Windows has the rare case of multiple bootable sequences/partitions.

In such a rare case, prior to apply this method, you need to make it to "only single bootable partition" by using "msconfig" - "boot" - "select present OS boot partition", and delete other bootable indicators/directors.

AFAIK, the system disk has only the one boot partition. I have never run this machine in a dual boot configuration with another OS.

 

[dualazmak]

AFAIK, the system disk has only the one boot partition. I have never run this machine in a dual boot configuration with another OS.

Please double check it by "msconfig" - "boot"; if you have only present Windows OS boot partition in it, it should be OK for upgrade procedure by "setup.exe /product server" as I shared in my post #1!

After you could successfully upgrade to Windows 11 25H2, you would please briefly share your setup and procedure on this thread; such sharing of successful event will be nice reference for many people following this thread.

 

[MRC01]

Yes...
By this procedure, you can bypass all of the TPM check, CPU check, RAM check, and SecureBoot check!

I used Rufus.ie to upgrade my old 1TB HDD from Windows 10 to 11, and it worked flawlessly. It skipped the TPM and CPU checks, plus all the annoying setup stuff like forcing a Microsoft account.

I run Linux on all my machines, but I still need Windows for a couple of apps, so I run Windows 10 in a VirtualBox VM. I'll need to upgrade this to Windows 11 since Windows 10 is being end-of-lifed and apps (like Turbotax!) will no longer run on it. The Windows upgrader refused, saying my VM didn't meet requirements - mainly, not having TPM & SecureBoot. Adding them would be painful, either wiping the entire VM (and my apps & data), or going through some long tedious workarounds.

These "requirements" are entirely arbitrary, as there's no technical reason Windows 11 needs them. Microsoft may recommend them, but refusing to upgrade without giving the user an option to decline adds capricious arrogance to their arbitrary decision.

Flyobee to the rescue! https://github.com/builtbybel/Flyoobe
Flyobee is an open source project that does several things:

• Like Rufus, it installs Windows 11 allowing users to bypass the "requirements". This includes in-place upgrades preserving apps & data.
• It facilitates downloading the Windows 11 ISO file, providing several methods.
• After the installation is complete, it facilitates disabling junk, ads, AI spyware, and & bloat-ware you don't want.

Even if you already have Windows 11, Flyobee is worth the time just to disable all the junk and configure your system to your taste.

 

[Petrushka]

I run Linux on all my machines, but I still need Windows for a couple of apps, so I run Windows 10 in a VirtualBox VM. I'll need to upgrade this to Windows 11 since Windows 10 is being end-of-lifed and apps (like Turbotax!) will no longer run on it. The Windows upgrader refused, saying my VM didn't meet requirements - mainly, not having TPM & SecureBoot. Adding them would be painful, either wiping the entire VM (and my apps & data), or going through some long tedious workarounds.

These "requirements" are entirely arbitrary, as there's no technical reason Windows 11 needs them. Microsoft may recommend them, but refusing to upgrade without giving the user an option to decline adds capricious arrogance to their arbitrary decision.

Flyobee to the rescue! https://github.com/builtbybel/Flyoobe
Flyobee is an open source project that does several things:

• Like Rufus, it installs Windows 11 allowing users to bypass the "requirements". This includes in-place upgrades preserving apps & data.
• It facilitates downloading the Windows 11 ISO file, providing several methods.
• After the installation is complete, it facilitates disabling junk, ads, AI spyware, and & bloat-ware you don't want.

Even if you already have Windows 11, Flyobee is worth the time just to disable all the junk and configure your system to your taste.

When you say the security features are unnecessary, you misunderstand the reason for Windows 11.

I think the interface is an improvement, but that’s not the reason for the version. Security is the reason.

Apple will not upgrade my wife’s Mac for the same reason. Lacks current security hardware. It is unclear if software requiring the security chip will run on a crippled W11 machine.

 

[MRC01]

When you say the security features are unnecessary, you misunderstand the reason for Windows 11.
I think the interface is an improvement, but that’s not the reason for the version. Security is the reason.
Apple will not upgrade my wife’s Mac for the same reason. Lacks current security hardware. It is unclear if software requiring the security chip will run on a crippled W11 machine.

No misunderstanding, I know why they do this. My point is that companies can recommend people use TPM, Secure Boot or other features. And even enable it by default. But users should make the ultimate decision, and disable it if they want to. For example, in my case the Windows OS runs in a VM inside a secure Linux server. I don't need TPM or Secure boot, which why it's arrogant and capricious for Microsoft to force their over-simplified "one-size-fits-all" decision on me (and millions of other users).

PS: my purpose here is not to complain about Microsoft, but to help others escape from Microsoft's over-rigid enforcement of arbitrarily invented "requirements" and upgrade their systems to Windows 11, if they want/need to. I hope the info I provided will be as helpful to them as it was to me.

 

[Joe Smith]

Switched our unsupported Lenovo towers to Linux Mint 22 a few months ago, delighted with the experience. Done with Windows for now, going to live contentedly with a Chromebook and the various MInt PCs. Going to get a very low spec HP Windows laptop (4 gb ram, 32 gb flash hard drive) running on Mint XFCE version in October.

 

[pablolie]

I am have been running Win11 on non-supported CPUs for a while (but both machines support TPM2.0 - computers need to be really old to not support TPM). I have never had a single issue with the twice-a-year big updates. And truly, the performance is very good (they were top spec machines in their time).

But of course Windows can not compare with Linux. One of my favorite (and extremely functional) computers is a 10-year old Lenovo Thinkpad X250 running Ubuntu 24. Works like a charm, even the web-based Office apps don't even remotely tax it.

 

[MRC01]

... But of course Windows can not compare with Linux. One of my favorite (and extremely functional) computers is a 10-year old Lenovo Thinkpad X250 running Ubuntu 24. Works like a charm, even the web-based Office apps don't even remotely tax it.

I do the same with our phones & tablets. They all run LineageOS, the open source version of Android. No manufacturer or carrier bloat-ware or spy-ware, better battery life and performance. And no planned obsolescence. My devices are 5+ years old running the latest version of Android with weekly updates years after the manufacturers abandoned them.

I do wish LineageOS were as easy to install on phones as Linux is to install on laptops & desktops. This would make it more accessible and popular. But phones & tablets have locked bootloader & recovery software that some manufacturers try to make as difficult as possible to unlock. One can get around this but it's not for the faint of heart.

 

[dualazmak]

Let me repeat my note and warning shared on top of this thread...

Note and warning:
The Windows 25H2 upgrade installation procedure shared in this post is just for your reference; if you would like to apply this to your PCs, do it with your own responsibility and risks.

As for the security concerns in my (and my wife's) PCs running Windows 11 Pro 24H2 or upgraded 25H2, I always subscribe the latest version and all the security features (including e-mail security scanning and filtering) of ESET Internet Security on Windows in all the PCs.

Furthermore, just for your reference, for two of my outdated PCs, I have been, and I am, testing Ubuntu/Linux OS and Chrome OS, having three independent bootable 256 GB or 512 GB OS-SSDs of Windows 11 Pro, Ubuntu, Chrome OS, respectively; the three SSDs can be physically and completely-independently replaced/exchanged via SATA and SATA-power cables that are pulled-out to the front of the each PC case/chassis.

In any way, I will soon upgrade all of (rest of) my and my wife's Windows 11 Pro 24H2 PCs (including outdated NUC PCs and note-book PCs) to Pro 25H2 by the "setup.exe /product server" method in 25H2 Insider Preview .iso package shared in my post #1; as far as possible, I will share each PC status and upgrade result for your reference.