Windows Installer Service Unavailable — How to Fix This Issue

If you encounter the error message “Windows Installer Service Unavailable” while trying to install software on your Windows system, several factors might be causing this issue. Let’s explore why this error appears and how you can resolve it effectively.

Possible Causes of the Error

  • The Windows Installer service is disabled or not functioning properly.
  • System files are corrupted or missing.
  • Malware or viruses have altered service settings.
  • The installer file version is incompatible with your current Windows version.

Ways to Fix the “Windows Installer Service Unavailable” Error

1. Restart the Windows Installer Service

Sometimes, simply restarting the service can resolve the issue. Follow these steps:

  1. Press Win + R, type services.msc, and press Enter.
  2. Find Windows Installer in the list of services.
  3. Right-click on it and select “Restart”. If the option is unavailable, click “Start” instead.
  4. Ensure the startup type is set to “Manual” or “Automatic”.

2. Re-register the Windows Installer Service

In some cases, the service may not be registered correctly. To fix this, you can use the following commands:

  1. Open Command Prompt as an administrator (right-click the Start menu and select “Command Prompt (Admin)” or “Windows PowerShell (Admin)”).
  2. Type msiexec /unregister and press Enter.
  3. Then type msiexec /regserver and press Enter again.
  4. Restart your computer and try installing the application again.

3. Check System File Integrity

The error might be caused by corrupted system files. Use the built-in Windows tools to verify and fix them:

  1. Launch Command Prompt as an administrator.
  2. Enter the command sfc /scannow and press Enter.
  3. Wait for the scan and repair process to complete. It may take a while.
  4. Restart your computer once the scan is finished.

4. Modify Permissions in the Registry

Sometimes, the issue is related to permission restrictions for the Windows Installer service. Follow these steps to adjust them:

  1. Press Win + R, type regedit, and press Enter.
  2. Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\msiserver.
  3. Right-click the msiserver folder and choose “Permissions”.
  4. Ensure that the group “Everyone” has both “Read” and “Full Control” checked.
  5. Click OK and close the Registry Editor.

5. Update Your Windows System

If the problem persists, it may be due to outdated system components. Check for Windows updates:

  1. Open Settings (Win + I) and go to “Update & Security”.
  2. Click “Check for updates” and install any available updates.
  3. Restart your computer after installing the updates.