Software⏱️ 3 min read📅 2026-06-11

How to Fix 0x80070666 Error – vc_redist_2015 Setup Failed: 0x80070666 Unspecified error

Error 0x80070666 occurs when installing Microsoft Visual C++ 2015 Redistributable on Windows 10 64-bit.

Quick Answer: Check if the system has the required .NET Framework version and try reinstalling or using a different installer.

📋 Table of Contents

  1. 💡 Why You Are Getting This Error
  2. ✅ Best Solutions to Fix It
  3. 💡 Conclusion

The error 'vc_redist_2015 Setup Failed: 0x80070666 Unspecified error' occurs when attempting to install the Microsoft Visual C++ 2015 Redistributable (x86) on Windows 10 64-bit. This issue affects users who have downloaded the vc2015 installer from Microsoft and are trying to run it on their system.

This error can be frustrating as it prevents users from installing a crucial component required for various development tools and applications. Fortunately, this guide provides step-by-step instructions to troubleshoot and resolve this issue.

💡 Why You Are Getting This Error

  • The primary reason for this error is the incompatibility between the installer package and the Windows operating system. The vc_redist_2015 installer may not be compatible with Windows 10 64-bit, leading to the 'Unspecified error' (0x80070666) during installation.
  • Another possible cause could be a corrupted or incomplete download of the installer package, which can result in an invalid installation process.

✅ Best Solutions to Fix It

Installing the Visual C++ Redistributable via the Microsoft Installer

  1. Step 1: Download and install the Visual C++ Redistributable from the official Microsoft website. Ensure that you download the correct version for your system (x86 or x64).
  2. Step 2: Run the installer and follow the prompts to complete the installation process.
  3. Step 3: After successful installation, verify that the Visual C++ Redistributable has been successfully installed by checking for its presence in the Windows Feature Manager.

Installing the Visual C++ Redistributable via the vcredist_x86.exe installer

  1. Step 1: Locate the downloaded vc_redist.x86.exe file and run it as an administrator.
  2. Step 2: Follow the installation prompts to complete the setup process. Ensure that you select the correct installation options for your system (x86 or x64).
  3. Step 3: After successful installation, verify that the Visual C++ Redistributable has been successfully installed by checking for its presence in the Windows Feature Manager.

💡 Conclusion

To resolve the 'vc_redist_2015 Setup Failed: 0x80070666 Unspecified error', you can try installing the Visual C++ Redistributable using either method (1) or (2). If you encounter any further issues, consider seeking assistance from Microsoft support or a qualified IT professional.

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