FIX: Microsoft Visual C++installation error 0x80070666

by Matthew Adams

Windows & Software Expert

May 26, 2020

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Error 0x80070666 is a Microsoft Visual C++ installation error. The issue arises for some users when they try to install Microsoft Visual C++ packages (usually C++ 2015 Redistributable) on Windows. The full error message states this:

One or more issues caused the setup to fail… 0x80070666 – Another version of this product is already installed. Installation of this version cannot continue. To configure or remove an existing version of the product, use the Add/Remove Programs.

Users can’t install the required Microsoft Visual C++ package when that issue arises. The error 0x80070666 message, however, does provide a subtle hint as to how to fix the issue. This is how you can fix error 0x80070666.

How do I fix Visual C++ error 0x80070666?

1. Uninstall Visual C++ packages already installed

1. Other Visual C++ packages, such as Visual C++ 2017, can block the C++ 2015 installation.
2. To fix that, press the Windows key + R hotkey.
3. Type appwiz.cpl in the Open text box and click OK to open the uninstaller Windows.
   
4. Select a Microsoft Visual C++ package to uninstall.
5. Click the Uninstall option.
6. Then go through the uninstall guidelines to remove the software.
7. Repeat steps three to five to uninstall all Visual C++ packages.
8. Restart Windows after uninstalling the Visual C++ package.
9. Then try installing the Visual C++ package error 0x80070666 arises for.

2. Check for Windows updates

Error 0x80070666 can be due to pending updates that are already about to install the same C++ package that users are trying to install.

1. To check for Windows updates, press the Windows key + S keyboard shortcut.
2. Type the keyword update in the search box.
3. Click Check for updates to open the Settings tab shown directly below.
   
4. Then press the Check for updates button. Windows 10 will download pending updates.
5. Thereafter, you’ll need to restart Windows.

3. Repair the Visual C++ installer

Some users have also confirmed they’ve fixed error 0x80070666 by repairing downloaded Visual C++ installers.

1. To do that, open Windows 10’s search utility.
2. Next, enter cmd in your search box.
3. Right-click Command Prompt to open a context menu for it. Select the Run as administrator option on that menu.
4. Then you’ll need to enter a change directory command for the folder that includes the downloaded Visual C++ installer.
   • The command should look something like this (with an edited path):
     • CD C:Users*YourUser*Downloads.
5. Press the Enter key after entering the CD command.
6. Then enter this command:
   • vc_redist.x64.exe /uninstall.
     
7. Click the Repair button on the window that opens.

4. Check out the Program Install and Uninstall troubleshooter

If the above fixes don’t do the trick, check out the Program Install and Uninstall troubleshooter.

1. That’s not included with Windows 10, but you can get that troubleshooter by clicking Download on its webpage.
2. Open the troubleshooter’s window, and click Advanced to select the Apply repairs automatically option.
   
3. Click the Next option.
4. Select the Installing option.
5. Select the Visual C++ package that error 0x80070666 arises, and press the Next button.

Those are a few of the more widely confirmed resolutions that have fixed error 0x80070666 for users. So, they’ll probably resolve the issue so you can install the required Visual C++ package.

If you are aware of another fix for this issue, help the other users by sharing it in the comments section below.

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