Hi 56Willys,
Seems like another installer service is still running in background after reboot which is blocking the Lightroom installer.
Open task manager and go to processes tabs> choose show processes from all users at the bottom> Look for the microsoft installer process (msiexec) and end it.
Then, run the installer for Lightroom.
Regards,
Chetna
Chetna,
That was it. Interesting how the msi continued to run after a reboot.
Thanks for your help
Bob Kelly