Windows Installer is a core service that manages the installation of everything in Windows, including apps, features, and many other things. If it breaks, you will be stuck with new installations and even app upgrades.

In this post, we will share a list of error codes and their solutions, some pointing to our existing solution, and how to solve them.

The first thing we would suggest is to run the Program Install and Uninstall Troubleshooter to repair issues that block program installation or removal because of corrupted registry keys. This program will fix corrupted registry keys on 64-bit operating systems, which control the update data, problems that prevent existing programs from being completely uninstalled or updated, and problems that block you from uninstalling a program through Add or Remove Programs (or Programs and Features) in Control Panel

In the Run prompt, type MSIExec, and then press Enter.

If you get the Windows Installer window which tells you everything about MSIExec, then it’s all good.

If you get an error, you might have to start it manually.

Right-click on the taskbar, and select Task Manager. Switch to Services, and look for msiserver. Start it.

You can also run services.msc to open Windows Services and go to Windows Installer, and restart it.

You may see the message Windows Installer Service could not be accessed. This usually happens if the Windows Installer Engine is corrupted, installed incorrectly, or disabled. You will need to fix either the corruption or fix the configuration or enable it. The linked post also solves the issue where the Windows Installer service could not start, and gives the message as Error 5, Access is denied.

If the Windows Installer package faces unstable network access during the uninstallation or installation process, sometimes, the error might appear if you fail to complete the process successfully. The error message might go like “There is a problem with this Windows Installer package. A program required for this install to complete could not be run. Contact your support personnel or package vendor.” 

Usually, the Windows Installer or msiexec.exe runs in the background. You can check in the Task Manager under the list of processes that are running. However, if you see it constantly running, and the Windows Installer keeps popping up, it means it is stuck. It is possible that an installation is not able to complete, and this happens as a result.

Read: Windows Installer Service missing.

If you are not able to install software that you just downloaded from the internet, and it keeps throwing the error message “Installation Package could not be opened“, then it’s probably a security issue. Windows many a time blocks applications you download from the internet as it does not trust them. You may have to unblock it or disable your antivirus to fix it.

If nothing works, the best option in our experience is to re-register the Windows Installer service. The reason why it works great because it fixes registry issues as well, and gets the basic settings ready again.

Launch the command prompt with admin privileges. Type the following commands and hit Enter after each one.

Close the command prompt, save all your work, and restart your computer.

Check if you are facing Windows Installer issues.

Windows OS maintains a Windows Installer cache. Any files you install are temporarily extracted here and then installed on the PC. If you are deleting files from here manually or during installation or any other program is doing that, you will get an error.

To check the version of Windows Installer on your computer, open the Run box, type msiexec -? and hit Enter. You will see the version mentioned at the top.

Since the Windows Installer is a system file, the best way to repair or fix a corrupted Windows Installer is by running the built-in System File Checker. Alternatively, you could search for the latest version of Windows Installer file on the Microsoft.com website and download it from there,

Useful link: How to enable Windows Installer logging.