While trying to install an .msi file in a machine with Windows Vista as OS, we encounter an error stating that :

“The installer has encountered an unexpected error installing this package. This may indicate a problem with this package. The error code is 2869.”

This happens because of UAC (user access control) feature of Windows Vista.

If you are defined as administrator on Vista, actually you are only temporarily granted administrator privileges when running programs.

Therefore MSI Custom Actions that interact with the system and require administrative privileges will fail to run.

Steps to resolve this issue :
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1) Copy the .MSI file to the root directory of your main hard drive (i.e. C:\).

2) Open Windows Notepad.

3) Copy this text into windows notepad:

msiexec /i C:\program_name.msi

(You can write the total path of your .msi file in the system, after msiexec /i.)

4) Replace the text “program_name” in the code that you copied with the actual name of the    .MSI file .

5) Click File -> Save As…

Instead of saving it as a .txt file, change the file name to installer.bat.

Save the file to your desktop.

6) On your desktop, right click on the file and select Run as Administrator.

This will run the .msi file properly to install the application in the system.