As I tried to install Fixpack 2 for Lotus Notes 8.5.1 today the installation failed with the message “Error encountered while installing Notes Core Hotfix component.”.
After some investigation I found that the JQS.EXE process (Java Quick Starter) seems to conflict with the installer (or has one of the Notes processes in use, although I cannot explain why).
As soon as I killed JQS.EXE with the Windows task manager the installation succeeded. Maybe this will help others with the same issue …
Error installing FP2 for Lotus Notes 8.5.1
I had the same issue several times even for older Notes updates.
In other installations, I had the problem during upgrades, when the NSD service was still running. So the best advice is to stop the NSD service (in Windows) and then check if any of the wel-known Notes or Domino processes are still running.
I had stopped all well-known processes before. Just did not realize that the Java Quick Starter seems to have something to do with Notes.
BTW: If you cannot find out which process is blocking the setup you can try to start the Fixpack installer for the Notes basic client. This installer exactly tells you what process is preventing the setup 🙂