You double-click a setup file ending in .msi, and Windows Installer shows a message: “This installation package could not be opened. Verify that the package exists and that you can access it, or contact the slot88 application vendor to verify that this is a valid Windows Installer package.” When Windows 10 this installation package could not be opened stops an install, the problem is usually the file itself or where it is stored.
Windows Installer needs to read the whole .msi file before it starts. If the download was interrupted, the file is blocked by Windows security, or the installer cannot reach the folder it is in, it gives up with this message.
Files run directly from a network drive, a zip archive, or a cloud folder that has not fully downloaded are common examples.
Most of the time, a fresh download saved to a local folder solves it.
Why This Happens
The installer fails to open for these reasons:
- The .msi file is incomplete or corrupted.
- Windows has blocked the file because it came from the internet.
- The file is run from inside a zip archive or a network location.
- The Windows Installer service is not running.
Antivirus software can also quarantine part of an installer while it is downloading.
Start With These Basic Checks
Prepare a clean copy of the installer.
- Download the installer again from the software maker’s official website.
- Save it to a local folder such as Downloads, not a network drive.
- If it came in a zip file, right-click the zip, choose Extract All, and run the extracted .msi.
- Right-click the .msi, choose Properties, and tick Unblock if the option appears.
- Run the installer again.
Compare the file size with the size listed on the download page to confirm it finished.
Going a Step Further
Check Windows Installer.
- Press Windows + R, type services.msc, and press Enter.
- Find Windows Installer, right-click it, and choose Start.
- Open an administrator Command Prompt and type msiexec /i “C:\path\to\file.msi” with the real path.
- Temporarily pause antivirus protection during the install if it blocks the file, then turn it back on.
- Run sfc /scannow if all installers fail.
If only one package fails, contact the software maker for a different version or an .exe installer.
A Word of Caution
Only run installers from sources you trust. A file that fails because it was tampered with is safer left unopened. Re-enable antivirus straight after installing.
Final Thoughts
This MSI error usually means the installer file is incomplete, blocked, or stored somewhere Windows Installer cannot read. Download it again to a local folder and unblock it.
