From where did these [uninvited] backup files came from?

maybe I didn’t write clear

I see this just as you wrote

That means the command is properly in the case that no error has been record. When you save a file, there should be an error message recorded as to why the temp file could not be moved to the trash. This is what I’m after and unfortunately you aren’t getting any output in this case

Maybe the fact that i’m using DropBox has something to do with the issue?
[which in it new version create a long and strange file path]

Currently with the build Wim gave me, I can’t see any Temp file… does these have a location [I want to see if they are pilling up ]

The temp file is being deleted because Rhino is not able to move it to the trash.

I hope you can find a solution.

The old MacOS system seems to still work pretty well, I had many crashes these last days [force quit to be precise] and did not loose anything .