Here’s How to Fix Windows Installer Not Working


Windows Installer is the software component and application programming interface (API) of Microsoft Windows responsible for installing, maintaining, and removing applications.

You can identify that there is a problem with your Windows installer if you see one of the following messages:
  • Unable to access Windows Installer Service.
  • The Windows Installer service failed to start.
  • Unable to start the Windows Installer service on Local Computer. Error 5: Access is denied.

Unless you fix your Windows installer, you won’t be able to install new apps, update or remove installed apps. If the Windows installer has put a damper on your planned activities, don’t worry because we are equipped with our own tools to help you solve this crisis.

How to Fix Windows Installer Not Working?

Below, we’ve listed a few different fixes that you can try to fix your problem with Windows Installer not working properly. Please go through the list one by one until your issue is resolved.

Run the troubleshooter

You can try to let Windows Troubleshooter fix this problem automatically. Make sure you can use administrative privileges and follow the steps below:

  1. To download “Program Install and Uninstall Troubleshooter” and run it.
  2. On the next screen, select if you are having a problem with Facility Where Uninstallation an application.
  3. Select the program with which you are having a problem.
  4. Follow the instructions on the screen.

Virus/malware scan

Your Windows installer may not work properly because it has been infected with a virus or malware.

Viruses and malware usually attach themselves to system files and hijack program functionality, usually prioritizing their own execution over the program’s function, thereby breaking it. Sometimes they can also create a duplicate file, which is called instead of the actual system program, which could also be the case here.

Run a virus scan to see if this is the case and fix it.

  1. Press Win + I to launch Settings.
  2. Move towards Privacy and Security > Protection against viruses and threats.
  3. Make sure your Virus and threat protection updates are up to date.
  4. Click on Quick scan and wait for the process to complete.
  5. If a virus or malware is detected by Windows Security, take corrective action (quarantine Where remove), and perform a Full scan of your system.

Restart the Windows Installer Service

You might have problems installing or removing programs because the Windows Installer service is not working properly. If you see an error message related to the Windows Installer service (for example, the Windows Installer service could not be started), you should check if the service has stopped.

You will need to start the service if it has stopped. If it has already started, you can try stopping it and then restarting it.

You can restart the Windows Installer service using the Service Manager or Task Manager.

Using the Windows Service Manager

  1. Press Win + R and type services.msc throw Windows Service Manager.
  2. Scroll to Windows Installer and right click on it, click Properties.
  3. Look for the status under Service status
  4. Click on Stop then click Begin. (If the service status already says “Stopped,” click on Begin.)
  5. Try installing/uninstalling the app again.

Restart Windows Installer Using Task Manager

The Windows Installer service can also be started/restarted from Task Manager.

  1. Press Ctrl + Shift + Esc to launch the Task Manager.
  2. Switch to the Services tab and scroll down to find msiserver. This service is the Windows Installer Service.
  3. Right click on msiserver and select Begin. If the status is Functioning already, you can instead select To restart.

This should start the Windows Installer service. Now try installing or uninstalling apps to see if the issue has been resolved.

Re-register Windows Installer

Another attempt is you can try re-registering the Windows installer and see if that fixes the problem.

  1. Press Win + R and type ordered to launch the command prompt.
  2. At the prompt, type: msiexec /unregister and press enter..
  3. Then type msiexec /regserver and press enter.
  4. Try and see if you can install/uninstall now.

Reset installer service in registry

Microsoft has provided a way to edit your registry for this particular case, which resets the installer configurations. This will hopefully solve your problem with the installer not working.

  1. Press Win + R and type notepad to launch the notepad.
  2. Copy and paste the following into Notepad:
Windows Registry Editor Version 5.00

  1. Save file as WindowsInstaller.reg. Be sure to select “All file types” in the Save As window.
  2. Right click on the saved file and select Merge. (Windows 11 users: Right click > Show more options > Merge)
    RegistryWindowsInstallRight clickViewMoreOptionsMerge
  3. To restart the computer.

Remove the older version of the program you want to install

Sometimes you may encounter problems while installing a program if an older version of the program is already installed on the system. In this case, you must first remove the previous installation and then try to install the newer version.

  1. Press Win + R and type control panel to launch the Control Panel.
  2. Below Programsclick on Uninstall a program.ControlPanelProgramUninstall
  3. Scroll to the program in the list and right click on it. Then select Uninstall.
  4. To restart computer and try installing the latest version now.

Remove duplicate msiexec.exe Case

If a duplicate msiexec.exe file exists, it may conflict with a copy of itself. In this case, you can delete the duplicate file to fix the problem.

  1. Press Win + R and type %windir%SYSWOW64. For 32-bit systems, the path is %windir%system32.
  2. Locate msiexec.exe and see if there is a duplicate entry.
  3. Wipe off the duplicate file.

This should have solved your problem. Check for yourself by trying to install the app.


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