If you are looking for a download because of an error message (like "Windows Installer service could not be accessed"), downloading a file won't fix it because the service is already part of your system. Instead, you can reset the service: Command Prompt as Administrator msiexec /unreg and press Enter. msiexec /regserver and press Enter. Microsoft Learn
: Allows developers to specify security descriptors that can deny permissions or inherit them from parent resources. Windows Installer 5.0 Download For Windows 10 64-bit
net start msiserver