How to fix Error 1620 on Windows 11

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Troubleshooting Guide: Windows Installer Error 1620

Why This Error Happens

Error 1620 occurs when the Windows Installer service (msiexec.exe) is unable to properly read or open the installation package (.msi file). This is typically caused by a corrupted download, an incomplete file transfer, or damaged Windows Installer cache files (.msi packages stored in C:\Windows\Installer). It can also stem from insufficient system permissions or a malfunctioning Windows Installer service configuration.

Step-by-Step Resolution Guide

Step 1: Verify and Re-download the Installer File

  • Check the file size of the .msi package to ensure it matches the vendor’s listed size (a mismatch indicates corruption).
  • Delete the current installer file completely and clear your browser cache/downloads folder.
  • Re-download the installation package directly from the official vendor website, avoiding third-party mirrors.

Step 2: Restart the Windows Installer Service

  • Press Win + R, type services.msc, and hit Enter.
  • Locate Windows Installer in the list, right-click it, and select Restart.
  • If the service is disabled, right-click, go to Properties, and set Startup type to Manual or Automatic.

Step 3: Run the Installer with Elevated Permissions via CMD

  • Open Command Prompt as Administrator (right-click Start Menu > Terminal (Admin)).
  • Navigate to the folder containing the .msi file using cd C:\Path\To\Your\File.
  • Execute the command: msiexec /i "YourFileName.msi" to force a direct install bypassing potential shell execution glitches.

Step 4: Clear the Corrupted Installer Cache

  • Press Win + R, type %temp%, and delete temporary files that might be locking the installer.
  • If the error persists, run the Windows Update Troubleshooter via Settings > System > Troubleshoot > Other troubleshooters, as this often resets underlying Installer components.

Alternative or Verification Steps

  • Verify the Fix: Attempt to run the .msi file again by double-clicking it; if it opens the setup wizard without the 1620 error, the installer service has been successfully repaired.
  • Alternative Solution: If the error continues, use the MSIcuu2.exe (Windows Installer CleanUp Utility) or the Program Install and Uninstall Troubleshooter from Microsoft’s support site to remove orphaned registry entries related to the failed installer.