Having an issue with Windows Installer. I keep getting to notice that it is not installed.

msiexec.exe is in C:windows\system32 but I cannot get it to run with above instructions indicated running a Windows repair install (in-place upgrade using the Windows installation media while keeping files and apps) is a common fix,

I upgrade from Windows 10 Pro to Windows 11 Pro when Microsoft offered the upgrade so DO NOT have an Windows Installation media ... So how do I solve this now; as msiexec.exe service is not in services or running.

Windows Installer (msiexec) is not something you normally reinstall as a separate package in modern Windows. It is built into the operating system, so when you see messages that it is “not installed,” it usually means the service is disabled, the registration is broken, or system files are corrupted.

First, check whether the Windows Installer service is present and enabled. Press Win + R, type services.msc, and press Enter. In the list, find “Windows Installer.” If it exists, open it and set Startup type to Manual. If the service is stopped, try starting it. If it is missing entirely, that usually points to deeper system corruption rather than a simple uninstall.

A common fix is to re-register the Windows Installer engine. Open Command Prompt as Administrator and run the following commands one at a time:

msiexec /unregister
msiexec /regserver

If the system is 64-bit and you still see issues, you can also re-register the 32-bit version explicitly:

C:\Windows\SysWOW64\msiexec.exe /unregister
C:\Windows\SysWOW64\msiexec.exe /regserver

After that, repair system files because Windows Installer errors are often caused by corrupted system components. Run:

sfc /scannow

When that completes, also run the DISM repair tool:

DISM /Online /Cleanup-Image /RestoreHealth

Restart the laptop after these complete and test installing or uninstalling a program again.

If the alerts are still appearing even when installations work, it is often a broken association in the registry or a malfunctioning application repeatedly calling msiexec incorrectly. In that case, running a Windows repair install (in-place upgrade using the Windows installation media while keeping files and apps) is a common fix, because it refreshes the Installer components without wiping your data.

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hth

Marcin