Installing .MSI Files on Vista

In common with many other software packages that are packaged as Microsoft Installer (.MSI) files, Qlockwork did not always install correctly on Windows Vista.

The reason that the installation didn't work under Vista was the new User Account Control (UAC) feature. This is a security feature that changes the default user permissioning to make it much harder for malware to affect a Vista machine – but with the downside that .MSI files like the Qlockwork installer are less likely to install correctly.

The Workaround

Note: This workaround explicitly bypasses the added security features of Windows Vista, so use this method at your own risk. Only use this method to install software which you are sure is safe, like Qlockwork.

• Run a command prompt as 'Administrator'.
  • In the Start menu, navigate to "All Programs", "Accessories"
  • Right-click on "Command Prompt".
  • Select 'Run as administrator' from the menu.
  • Select 'Continue' in the User Account Control permission dialog.
  • A window with title "Administrator: Command Prompt" should launch.
• Run the Microsoft Installer by hand from the command prompt.
  • In the command prompt window, change directory to the directory where the installer file is stored. For example, if it is stored on the desktop, then run "cd \Users\dmd\Desktop".
  • Run the Microsoft Installer program on the installer file: "msiexec /i Qlockwork_1_2_2.msi".
  • Work through the installer process as normal.

The Technical Details

Under UAC, even if a user is an Administrator, their programs don't run with administrative privileges by default. If a program needs to make a change to the system, Vista checks with the user before upgrading the program to have these privileges; this is the cause of the various permission dialogs that quickly become familiar in Vista.

For programs, it is possible to skip the permission question by running the program under the special 'Administrator' account: right-click the program in Explorer, and select "Run as administrator" from the menu. (To clarify: the 'Administrator' account is different from a user account that has 'Administrator' privileges. The latter can be upgraded – via the permission dialogs – to have full privileges; the former has full privileges all the time.)

This approach works for installer programs that are executables (.exe files), but does not work directly for applications that are packaged as Microsoft installer files (.msi files). These installer files are associated with the Windows Installer application (msiexec.exe), in the same way that Word documents (.doc files) are associated with the Microsoft Word application (winword.exe). Because an installer file is not itself a program, it can't be run directly and so there is no "Run as administrator" option in the right-click Explorer menu for it.

To get around this, we can take advantage of the fact that once one program is running as 'Administrator', any programs that are kicked off by that program also run as 'Administrator'.