How To Fix Error Code 0x80070666 While Installing Microsoft Visual C++ Redistributable

If you’re trying to install Microsoft Visual C++ Redistributable and suddenly get the error “0x80070666 – Another version of this product is already installed,” don’t worry — you’re not alone. This is a common issue that happens when your system already has the same version (or a newer one) of the Visual C++ runtime, or when there’s a pending Windows update or incomplete installation interfering with the process.

In this guide, we’ll explain what causes this error, then walk you through several effective ways to fix it on Windows 11.

What Causes the 0x80070666 Error

Before we jump into the fixes, it’s important to understand what triggers the problem. Here are the most common causes:

• A different version of Visual C++ Redistributable is already installed.
• The installer is corrupted or incomplete.
• Windows Updates or Office components (like Office 365 or Visual Studio) are using the same runtime.
• Previous installations didn’t uninstall properly.

This error basically means Windows found a conflicting installation of the Visual C++ package, preventing the installer from continuing.

How to Fix Error Code 0x80070666 on Windows 11

Let’s go through the step-by-step methods to resolve the issue.

1. Check Installed Visual C++ Versions

1. Press Windows + R to open the Run dialog box.
2. Type appwiz.cpl and press Enter — this opens the Programs and Features window.
3. Scroll through the list and check if the same Visual C++ Redistributable version is already installed.
4. If it is, uninstall it by selecting it and clicking Uninstall.
5. Restart your computer and try installing the package again.

Tip: Make sure you install both x64 and x86 versions if your software requires them.

2. Run the Installer as Administrator

Sometimes, the installer doesn’t have sufficient permissions to modify system files.

1. Right-click on the Visual C++ setup file.
2. Choose Run as administrator.
3. Follow the on-screen prompts to complete the installation.

This simple step can often bypass permission-related errors.

3. Use Windows Update

Outdated system files or pending updates may block certain runtime installations.

1. Press Windows + I to open Settings.
2. Go to Windows Update → Check for updates.
3. Install any available updates and restart your system.

Once done, rerun the Visual C++ installer. This ensures all dependencies are up to date.

4. Repair Existing Visual C++ Installations

Instead of uninstalling, you can also repair your existing redistributables:

1. Go to Control Panel → Programs → Programs and Features.
2. Locate your Microsoft Visual C++ Redistributable versions.
3. Click on each one, then choose Change → Repair.
4. Once all are repaired, restart your PC and try reinstalling the package.

5. Uninstall Conflicting Software

Applications like Microsoft Office, Visual Studio, or older runtime libraries might use the same C++ components.

Try temporarily uninstalling or repairing these applications. After reinstalling the C++ Redistributable, you can put them back.

6. Install Using Command Line (Silent Mode)

If the normal installer keeps failing, you can run it in silent mode through Command Prompt:

1. Place the installer in an easy-to-access folder (like Desktop).
2. Open Command Prompt as Administrator.
3. Run the following command (replace filename with your installer’s name):
   vc_redist.x64.exe /install /quiet /norestart
4. Wait for it to finish. Then restart your PC.

This bypasses user prompts and sometimes avoids installer conflicts.

7. Remove Temporary Files and Registry Leftovers

Corrupted temp files or leftover registry entries can trigger the error.

1. Press Windows + R, type %temp%, and hit Enter.
2. Delete all the temporary files in the folder.
3. Use a trusted tool like CCleaner or manually remove old Visual C++ registry entries (advanced users only).
4. Reboot your system and reinstall Visual C++.

8. Use Microsoft’s Visual C++ Cleanup Utility

Microsoft provides an official tool that removes conflicting or broken redistributable installations.

• Download the Visual C++ Redistributable Cleanup Tool from Microsoft’s site.
• Run it and remove all existing Visual C++ packages.
• Restart your computer, then install the latest Visual C++ Redistributable 2022 version again.

Conclusion

The 0x80070666 error is typically caused by conflicting or incomplete Visual C++ installations. By uninstalling old versions, updating Windows, and using the cleanup tool if necessary, you can easily resolve it and get your programs running again.

If you frequently work with software that depends on Visual C++, consider keeping your redistributables updated using the latest Microsoft Visual C++ Redistributable 2022 package.