A new install of Mint MATE, another run at this question.  Caja is still dog-slow even on this fairly quick laptop (i5, 16 GB RAM).  It launches fast, but copying more than a handful of files is something it cannot handle and keep its UI updated along the way.  PCManFM doesn't have this problem, but I seem unable to make it the system default just the same way Caja is out of the box.Things I've tried this time:Simply setting the file manager in the Preferred Applications preflet.  This has no effect whatsoever that I can see, even after a system restart.After backing up caja, sudo ln /usr/bin/pcmanfm /usr/bin/cajasudo cp -s /usr/bin/pcmanfm /usr/local/bin/cajaThe latter two make it so that trying to launch the file manager from the quick launch icon (or whatever you call it in Linux)--which still points to caja--it simply stalls trying to launch for a while (there's a taskbar button, but no window, saying something like Starting...) and then that disappears.What I'm trying for:the desktop uses PCManFM even if that means the desktop itself displays nothing (why should I be running both Caja and PCManFM simultaneously?)plugging in a USB drive opens PCManFM, not Cajathe quick launch icon launches PCManFM (this part is fixable easily enough, but doesn't affect the above two)
Outright replacement of Caja with PCManFM on Mint 18.1 MATE
linux mint;file manager;settings;pcmanfm;caja