Project Not Cumulative

# Project Not Cumulative

Project Not Cumulative is an alternative approach to Windows cumulative updates designed to reduce update size, speed up installation, lower storage usage, and reduce unnecessary wear on hardware.

Instead of downloading a full cumulative MSU package from Microsoft every month, users can download a much smaller ESD package containing only the files updated since the previous Patch Tuesday release.

The goal of this project is to make Windows updates cleaner, faster, and more efficient for everyone, especially users with limited hardware, low storage capacity, or slower internet connections. It also benefits users with high-end hardware by reducing unnecessary disk activity and installation time.

At the moment, I am releasing Project Not Cumulative updates only for Windows 25H2 because it is the version I currently use and test regularly.

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# Why This Project Exists

Traditional cumulative updates continue growing over time because they include large amounts of previously released content. This increases:

- Download size
- Installation time
- SSD and storage wear
- Temporary disk usage
- Bandwidth consumption

Project Not Cumulative reduces these problems by delivering only the updated files needed since the last Patch Tuesday update already installed on the system.

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# How It Works

Instead of downloading a full 5 GB cumulative MSU package, users can download a much smaller ESD package, usually around 1 GB.

The ESD package contains only the new or modified files released after the previous Patch Tuesday update.

This update method works only if the system is already running the previous Patch Tuesday release.

Example:

- You already installed April Patch Tuesday
- You download the May Project Not Cumulative ESD package
- Only the files changed between April and May are installed

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# Benefits

- Faster update installation
- Smaller downloads
- Lower disk space usage
- Reduced SSD wear
- Less bandwidth usage
- Cleaner update process
- Better experience for low-end hardware
- More efficient even on high-end systems

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# Safety

The installation process is designed to remain safe because DISM installs only files officially distributed and digitally signed by Microsoft.

Unsigned or modified system files will not be accepted.

Even if Secure Boot is disabled or antivirus software is turned off, the installation process remains secure because only valid Microsoft-signed files can be installed.

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## Transparency

The ESD package can be opened and inspected easily using tools such as 7-Zip. Users can review the contents of the package without requiring special or proprietary tools.

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# Frequently Asked Questions

## Is this safe to install?

Yes. DISM installs only files officially distributed and digitally signed by Microsoft.

## Does this replace Windows Update?

No. This is an alternative update delivery method.

## Will this work on every Windows version?

No. Project Not Cumulative currently supports only Windows versions based on build 26100, including Windows 11 24H2 and 25H2.

## Why use ESD instead of MSU?

ESD packages are smaller and more efficient for distributing only modified files.

## Why is it called “Project Not Cumulative”?

Because the project focuses on delivering only the necessary updated files instead of massive cumulative update packages.
The name may sound unusual, but it describes the project’s goal very directly.

I'm moving this project to GitHub so all releases are in one place, it's much better. Here is the link to the project: github.com/jen1-sys/Project-Not-Cumulative/releases

Hi, interesting project!
The idea of delivering only the files changed since the last Patch Tuesday is genuinely clever, and I can see the appeal for users with limited storage or slow connections.

That said, I noticed a few concerns worth thinking about:

1. Strict sequential dependency - If a user misses even a single month's update, they're completely locked out of the next package and have to fall back to Microsoft's full cumulative update anyway. There's no catch-up mechanism, which makes the whole chain quite fragile in practice.
2. Out-of-band updates not covered - Microsoft occasionally releases emergency patches between Patch Tuesdays to address actively exploited vulnerabilities. Users relying solely on this project could remain unpatched on critical zero-days for weeks until the next regular cycle.
3. No automation - There's no integration with Windows Update or any auto-download script, so users have to manually monitor the GitHub repo, download, and install each month. For a project aimed at making updates easier and more convenient, that's a lot of manual overhead that somewhat undermines the goal.

Hope this feedback is useful - keep it up!

Thanks for the reply:

I do not see this project as a professional product. I created these updates mainly for myself, and I have been using them for almost a year. I was simply too busy to share them online earlier.

The goal is to provide smaller updates that are faster to download and more efficient to install. One of the main motivations is reducing environmental impact. Based on my calculations, if all Microsoft users used this method instead of standard Windows Update downloads, it could save up to 100 gigawatts of power per month.

That said, I will only release the update files that I personally create and use myself. As I mentioned before, everything you brought up is already covered in the FAQ.

This is not a replacement for Windows Update. It is simply an alternative method. Even I may occasionally miss a release, so users should always rely on Windows Update as the primary source of updates, not me.

However, for users who choose to use my updates, they can save time through smaller download sizes and faster installation speeds while also reducing energy usage. Hopefully, many people will find that worthwhile.