Windows Installer Service is not available - how to fix the error

This instruction should help if when installing any program in Windows 7, Windows 10 or 8.1, you see one of the following error messages:

• Windows 7 Installer Service is not available
• Failed to access the Windows Installer service. This may occur if the Windows installer is incorrectly installed.
• Could not get access to the Windows Installer Installer
• You may not install Windows Installer

In order, we will analyze all the steps that will help correct this error in Windows. See also: What services can be disabled to optimize work.

1. Check if the Windows Installer service is running and is it at all

Open Windows 7, 8.1 or Windows 10, To do this, press the Win + R keys and in the "Run" window enter the Services.msc command

Find the Windows Installer (Windows Installer) on the service list, click on it twice. By default, the service startup parameters should look like on screenshots below.

Please note that in Windows 7, you can change the type of startup for the Windows Installer - put "automatically", and in Windows 10 and 8.1 this change is locked (solution - Next). Thus, if you have Windows 7, try to enable automatic start-up service, restart the computer and try to install the program again.

Important: If you do not have a Windows Installer or Windows Installer service in Services.msc, or if it is, but you cannot change the type of starting this service in Windows 10 and 8.1, the solution for these two cases is described in the instructions failed to access the Installer service Windows Installer. There are also described a pair of additional methods to correct the error in question.

2. Manual error correction

Another way to correct the error associated with the fact that the Windows Installer Service is not available - re-register the Windows Installer service in the system.

To do this, run the command prompt on behalf of the administrator (in Windows 8, press Win + X and select the appropriate item, in Windows 7 - to find the command line in standard programs, click on it with the right mouse button, select "Run on the administrator name).

If you have a 32-bit version of Windows, then enter the following commands in order:

Msiexec / Unregister Msiexec / Register

This re-registers the installer service in the system, after executing the commands, restart the computer.

If you have a 64-bit version of Windows, then follow the following commands:

% Windir% \ System32 \ msiexec.exe / unregister% windir% \ System32 \ msiexec.exe / regserver% windir% \ syswow64 \ msiexec.exe / unregister% windir% \ syswow64 \ msiexec.exe / regserver

And also restart the computer. The error should disappear. If the problem persists, try manually run the service: Open the command prompt on the administrator name, and then enter the Net Start MSISERVER command and press ENTER.

3. Reset Windows Installer Service Settings in the Registry

As a rule, the second method is enough to correct the Windows Installer's error under consideration. However, if the problem could not be solved, I recommend to get acquainted with the way to reset the parameters of the service in the registry, described on the Microsoft website: http://support.microsoft.com/kb/2642495/en

Please note that the registry method may not be suitable for Windows 8 (accurate information on this account, I can not.

Good luck!