The Windows Installer Service Could Not Be Accessed
This error can occur if you’re running Windows in safe mode or if the Windows Installer is not correctly installed. Contact your support personnel for assistance.
You are probably here because you encountered this error while trying to install the Epic Games Launcher. While missing out on free games each week isn’t a crisis, this issue can also prevent you from installing essential software needed for work. In that case, it becomes a more serious problem.
Assuming you are not running Windows in safe mode, have all Windows updates installed, are using a 64-bit version of Windows, and have already tried multiple online tutorials with no success, then the error is likely tied to the Windows Installer Service.
Re-registering the Windows Installer Service
Even if this service appears to be running correctly, it is a good idea to re-register it. Follow these steps:
Open Command Prompt with administrative privileges.
Unregister the 64-bit version of the Windows Installer service.
Re-register the 64-bit version, located in the System32 directory.
Register the 32-bit version, located in the WoW64 folder (for compatibility with older software).
Running System Maintenance Commands
After re-registering the service, you should also execute two commonly recommended Windows repair commands:
DISM Command:
DISM /Online /Cleanup-Image /RestoreHealth
System File Checker (SFC) Scan:
sfc /scannow
These commands may take some time to complete, so do not shut down your PC. Ensure that your computer remains connected to the internet throughout the process.
Once the commands have finished, restart your PC. This time, your setup files should launch without issues.