Fix: NSIS “Installer Integrity Check Has Failed” Ubisoft Connect Error

The “Installer integrity check has failed…” error appears when launching the Ubisoft Connect setup during installation. This issue prevents the installer from proceeding due to problems with the installation files. The NSIS_Error originates from NSIS (Nullsoft Scriptable Install System) and typically means that the file is either incomplete or has been tampered with.
The most common cause is a corrupted installer file. Other possible reasons include browser cache issues during download, interference from antivirus software, or unstable internet connectivity.

In this article, we’ll explore several effective methods to fix this error.

1. Install Using Microsoft Store

1. Search for Microsoft Store in the Start menu and open it.
2. Type “Ubisoft Connect” in the search bar at the top.
3. Click “Get” and then “Install” to begin the installation.

2. Try an Older Stable Version or Re-download from the Official Site

Sometimes, the latest installer may fail due to packaging errors, download corruption, or compression issues that trigger the NSIS error. In such cases, you have two reliable options:

• Install a previously verified stable version known to work correctly. These versions are often more reliable and have been tested by the community.
• Re-download the latest installer directly from Ubisoft’s official website to ensure you’re using a clean, unmodified, and up-to-date package.

Once installed, Ubisoft Connect will automatically update itself if necessary.

Note: While Uptodown is generally considered safe, it is still a third-party source. Only download from trusted sites and avoid unofficial mirrors. For maximum safety, consider verifying the file’s digital signature or hash if it’s available.

1. Visit Uptodown to access older versions of Ubisoft Connect.
2. Select the January 2025 version.
3. Download and install the file.

If installing the older version doesn’t work, or if you prefer using the most recent files directly from Ubisoft’s servers, consider re-downloading the official installer. This ensures that you receive the latest, unmodified build with updated compatibility and patch fixes. It also helps if the error was caused by an incomplete or corrupted download.

1. Go to the Ubisoft Connect official site.
2. Click on “Download for Windows” and save the setup file.
3. Right-click the installer and select “Run as administrator.”

3. Install Ubisoft Connect via Steam or Epic Games

Steam and Epic Games handle the installation and verification of Ubisoft Connect when it’s required by a supported Ubisoft title. This avoids issues like file corruption, incomplete downloads, or integrity check failures that may occur when downloading through browsers.

1. Open Steam or Epic Games Launcher on your PC.
2. Go to your Library and select a Ubisoft game you already own (e.g., Far Cry 6).
3. Click Install or Play. The platform will automatically install Ubisoft Connect as part of the process.

This method ensures that you receive a clean, patched version of Ubisoft Connect bundled directly with the game, verified by the platform without manual steps.