New Windows 11 Installer vs Previous Versions – Any Real Difference in Stability?

Hi everyone,

With the release of Windows 24H2, Microsoft introduced a new installer experience. I'm curious to hear your thoughts:

Is it actually better to use the new installer compared to the previous one, especially if the goal is maximum stability and a clean installation on a brand-new laptop (without an OS)? Installation time or graphics performance doesn't matter—the only important goal is to end up with a stable Windows system after the installation process.

1. Have you noticed any tangible differences in system performance, reliability, or post-install behavior between the two?
2. Is the new installer just a cosmetic change, or does it improve the underlying setup process?
3. For those who prioritize long-term stability (e.g., for production machines), would you recommend sticking with the older installer or embracing the new one?

Looking forward to hearing your experiences and insights! Thanks.

about the installer, I prefer the old one (see my new post about it).

25H2 boot.wim, new setup wizard, same old bug with the $OEM$ folder.

Use the old one or the new one, depending on how you search in the setup wizard; in some cases, I can't use the new one.

The end result is the Windows installation, so nothing changes in the final environment, only the way to access it.

Mamukata said:

about the installer, I prefer the old one (see my new post about it).

25H2 boot.wim, new setup wizard, same old bug with the $OEM$ folder.

Use the old one or the new one, depending on how you search in the setup wizard; in some cases, I can't use the new one.

The end result is the Windows installation, so nothing changes in the final environment, only the way to access it.

Click to expand...

As far as I found from searching the internet, the new setup sometimes creates a Windows.old folder.
I had this issue myself, and I don’t think it’s very nice to see such a folder after installing a fresh copy of Windows.

What’s the reason for this? I think the new installer method of installation is a bit different from the old one... but I don't know what's the difference.

Garlin outlined some of the differences over here


If the Windows.old folder bothers you, just remove it. For example, if you have an unattend, you can run a FirstLogonCommand during the OOBE phase. This command will remove the Windows.old folder, only if it is empty.

The Windows.old folder allows you to roll-back to the previous version of Windows. Windows will delete it after 10 days or you can use Disk Cleanup or Storage Settings to delete it as soon as you want.

@kelper We're talking about the empty Windows.old folder that the newer versions of Windows Setup leaves behind on a fresh installation.

pseymour said:

@kelper We're talking about the empty Windows.old folder that the newer versions of Windows Setup leaves behind on a fresh installation.

Click to expand...

As far as I found from searching the internet, the new setup sometimes creates a Windows.old folder. Obviously, it should only create the folder if setup detects a previous installation and you are performing repair or upgrade installation.

Is that correct or does it always create it?

pseymour said:

If the Windows.old folder bothers you

Click to expand...

No. it's alright... it's just an empty folder after setup.

pseymour said:

Garlin outlined some of the differences over here

Click to expand...

Based on the explanation we can conclude that it's not just a different UI.
Which one do you prefer on a fresh SSD? old or new?

kelper said:

As far as I found from searching the internet, the new setup sometimes creates a Windows.old folder. Obviously, it should only create the folder if setup detects a previous installation and you are performing repair or upgrade installation.

Is that correct or does it always create it?

Click to expand...

I don't know about always 100%, but it sure seems like it creates it most of the time.

Sheikh said:

Which one do you prefer on a fresh SSD? old or new?

Click to expand...

I don't really prefer one over the other, but if I were automating Windows installs, I would start getting used to the new setup, in case Microsoft decides to ditch the old version entirely. I've seen some folks here mention little quirks here and there with unattends and what-not; you're going to need some time to work those issues out before MSFT removes the old setup, if they decide to do that.

pseymour said:

I were automating Windows installs

Click to expand...

I don't want to do that. I'm just curious about the difference between these two setups and the final result.

I do not know without testing if the installer has fixed the Hyper-V issue whereby installation to a vm virtual hard drive failed unless you used the old installer as identified by @Bree.

cereberus said:

I do not know without testing if the installer has fixed the Hyper-V issue whereby installation to a vm virtual hard drive failed unless you used the old installer as identified by @Bree.

Click to expand...

Hmmmm.... Sounds strange!

New or "Modern" Setup runs as a Windows upgrade scenario, even on a clean disk wipe. That's why it magically creates an empty Windows.old folder. You can't run an "upgrade" without referencing Windows.old.

In terms of installing an image, every WinPE Setup primarily has these tasks:

Modern Setup, aside from the UI changes, appears to be stricter about how the unattended file is written, and what is allowed for a sysprepped image.

There are numerous reports where experienced admins find a procedure they followed for previous releases stopped working, as soon as they moved to 24H2. Switching Setup back to the legacy version fixes whatever compatibility issue was blocking them.

How do you judge stability? Is it more stable because you can't "get away" with something that was tolerated by 23H2?

MS has never acknowledged in any official docs that they changed WinPE in 24H2, or any best practices for IT admins to follow, or how to work around compatibility issues. This why you see stories of admins hacking ISO's to use legacy Setup, or worse creating hybrid ISO's which use an older boot.wim to apply newer install.wim images.

If your install needs are boring, the two Setup clients aren't going to matter except for the stupid Window.old folder that doesn't get removed.

If your install depends on a sysprepped image, or doing advanced things during the winPE or specialize passes, you need to pay attention.

Personally I hate the new Setup, more because it's a pain to debug. The legacy Setup wrote its logging files in a well-known location, and updated them on the fly. I can't find the same level of debug info when new Setup dies in the specialize pass. Unless they're hidden in some folder I'm too dumb to find.

I just use an older win 11 23H2 image unattended which so far seems to auto upgrade to 24h2 when it searches for updates during the install. It honestly doesn't take that long so I dont have much reason to update it and then deal with the hassles of things breaking with the new setup installer. I don't know how long that will work.

I created my unattended with karis excellent tutorial here awhile ago


If someone knows, that would be helpful. I would assume as long as its able to check for updates it might even be fine to take it to 25h2 when that releases.

I haven't been up to date much on this whole new setup or how it affected unattended installs since then.

I've had fairly complex RunSynchronous commands not be executed (AFAIK). My guess is how Setup is parsing the answer file's encoding of commands with lots of escaped (or not properly escaped?) characters.

From the setupact.log, I might see "successfully executed XYZ", but my install looks like it never happened.