Firefox pdf plugin not remembering download directory and moving files from /run/user/XXX deletes them without a trace

[Ralf Mardorf]

If the menu bar is enabled go to

Edit > Settings

or in the URL bar type "about:preferences".

Scroll down to "Files and Applications"

1. Ensure that the "Download" settings are ok.

2. Check the "Applications" settings.

I suspect fixing a few settings there is all you need to do.

If not, "about:config" is the next step.

I often restore Firefox, Waterfox ... profiles after updates.

In my experiences things like this happen all the time when using
Firefox, Waterfox ... especially after updates.

IIRC it was last month when Waterfox started storing my PDF to an
unwanted location. I don't remember what I've done.

I suspect the culprit is in "about:preferences" > "Applications"
settings.

I'm not aware of any satisfying web browser, by one way or another all
are a PITA, whatever operating system is used.