Error: The Windows Installer service could not be accessed this can occur if you are running Windows in safe mode or if the Windows Installer is not correctly installed.
Intuit recommends more than one solution for this issue. First solution may resolve this issue. For best result, please follow the steps in order shown below.
Safe mode is a troubleshooting option for Windows that starts your computer in a limited state. Only the basic files and drivers necessary to run Windows are started. The words Safe Mode appear in the corners of your monitor to identify which Windows mode you're using.
Once your computer boots into safe mode:
If your computer is running on normal boot or still getting the same error after following the steps above, please proceed to solution 2.
Windows Installer manages how other programs are installed and uninstalled on your computer. Software publishers can use Windows Installer to help make the installation or uninstallation process more consistent from one program to another.
Check if the Windows Installer service is not set to Disabled:
If the Windows Installer is running properly and you are still getting the same error, please proceed to solution 3.
Note: Reinstalling a Widows Installer is a bit complicated and requires editing a Windows Registry. If the error persists after following the solutions above, Intuit recommends you consult a qualified IT professional or Microsoft as there may be damage to your operating system.