The best thing is to put the SD card into a card reader and plug that into USB before starting cura. Then after you slice, it will offer to put your files directly onto external media!
In March 2026, I had an issue where it took a full minute to load and display a file!! Meantime the console messages show it thrashing around trying to open USB and serial connections. Apparently the Cura developers view this as a "don't fix" issue. The recommendation is to find and remove a USB printer plugin.
On my Fedora 43 system I use "locate" to search for "Ultimaker". It finds:
/usr/lib/cura/plugins /usr/share/cura/resourcesI see /usr/lib/cura/plugins/USBPrinting, so I do this:
su cd /usr/lib/cura/plugins rm -rf USBPrintingThis works perfectly. Now when I use File--Open to select an STL file, the model appears instantly and I can slice right away!
Adventures in Computing / tom@mmto.org