Applying and removing fixes on Domino is usually a smooth process, but nasty surprises can result if you hit the infamous "Related process is still running" issue. Take these steps so you avoid the problem altogether.
Before you apply or remove a fixpack/hot fix you need to shut down Domino. This is typically done by a quit on the Domino Console or stopping the Windows service.
We also recommend disabling the Domino Service and stopping and disabling the "Windows Management Instrumentation" service, as it can cause problems. It might even be a good idea to do a reboot once that's all done.
The problem is that sometimes even these steps do not ensure that ALL processes that use Domino components have stopped. For example, when you run the installer, you might get a message like:
The trick is to find those processes and stop them.
Download Process Explorer https://docs.microsoft.com/en-us/sysinternals/downloads/process-explorer and run it
From the Menubar select "Find", then "File Handle or DLL"
In the "Handle or DLL substring" field, enter the path for the Domino Program directory and click Search.
You will now see a list of any Processes and, more importantly, their PID (Process IDs) that are still running.
Close or terminate those processes so you can continue without any nasty surprises.
Good luck upgrading. (Don't forget to re-enable those services!)