Thanks for the very speedy reply.
I’m no expert, but your explanation sounds plausible. In terms of running processes, while I see AxCrypt.exe in the Win Task Manager list whether I am using it or not, the emacs.exe is only present when an emacs window is open, so there does not seem to be an emacs server that starts on first invocation and then hangs around.
There are variants for different hooks into Win: https://www.gnu.org/software/emacs/manual/html_node/emacs/Windows-Startup.html
My .txt files are linked to runemacs.exe (84kB), which in turn seems to launch emacs.exe (8844kB). From item 1. on the page above, “The desktop shortcut should specify as its “Target” (in the “Properties” of the shortcut) the full absolute file name of runemacs.exe, not of emacs.exe. This is because runemacs.exe hides the console window that would have been created if the target of the shortcut were emacs.exe (which is a console program, as far as Windows is concerned). ”
So there are indeed multiple steps in opening the file.