Error 0x80070666


Several Windows users experience the “0x80070666” error when trying to install Microsoft Visual C ++, Lumberyard, or a similar distribution package. The error message is usually reported at the very beginning of the installation process. This particular problem is not specific to a certain version of Windows because it is confirmed that this is happening on Windows 7, Windows 8.1 and Windows 10.

How to Fix Error 0x80070666

Method 1: Uninstalling all current Visual C++ Redistributable packages

As many users have reported, this problem usually occurs if your computer already has a version (older or newer) of the same distributable package that you are trying to install.

In most cases, the error appears when the user tries to install Visual C ++ Redist 2015 while a newer installation is already present on this system. Several affected users reported being able to resolve the installation problem failed – installation error 0x80070666 by uninstalling the latest version.

Here is a quick guide on how to proceed:

  1. Press the Windows + R keys to open a Run dialog box. Then type “appwiz.cpl” and press Enter to open the Programs and Features screen.
  2. On the Programs and Features screen, scroll down the list of installed programs and locate all your Microsoft Visual C ++ Redist installations.
  3. Right-click each installation of Microsoft Visual C ++ Redist and choose Uninstall. Then follow the on-screen directions to complete the uninstall for each redist package.
  4. Once each Visual C ++ package has been uninstalled, restart your computer and wait for the next boot to complete.
  5. Try to install the same Redist package that previously failed with error 0x80070666.
  6. If you still have the same error message, proceed to the next method below.

Method 2: Running the Fix-It tool

There is a Microsoft Fix It tool that is used by multiple affected users to resolve the issue that prevents the automatic installation of the Redist package. This Fix It tool in particular will perform several repair strategies that will repair multiple components (including corrupted registry keys) used when installing new programs.

Here is a quick guide to using this Fix It tool to resolve error 0x80070666:

  1. Visit this link (here) and click the Download button to download the Fix tool.
  2. After downloading the tool, double-click on the .diagcab file to open the Fix It tool. Once the initial screen appears, click Advanced and make sure that the checkbox associated with Apply Auto Repair is checked. Then click Next to go to the next menu.
  3. At the next screen, click Install.
  4. Wait for the end of the inspection phase, select the redistribution package with which you are having problems, and then click Next.
  5. Follow the recommended repair strategies until the end of the program.
  6. Once the Fix It tool is finished, restart your computer and see if you can install the Redist package at the next boot without any problems.
  7. If you still encounter error 0x80070666, proceed to the next method below.

Method 3: Installing any pending Windows Updates

You may encounter error 0x80070666 because Windows Update is already preparing to install the same Redist package. Several affected users reported that during the necessary Windows update, the Redist package that previously failed with error 0x80070666 was automatically installed.

Here’s a quick guide to installing any pending Windows updates:

  1. Press the Windows + R keys to open a Run dialog box. Then type “ms-settings: windowsupdate” and press Enter to open the Windows Update tab of the Settings application.
  2. Once on the Windows Update screen, click Check for Updates and follow the on-screen instructions to install all pending Windows updates.
  3. After all the pending updates have been installed, restart your computer and check if the Redist package is not already installed. If it does not, try installing it and see if you still have the same error message.