Until recently, I have been able to transfer music files from my computer (ubuntu-22.0.4) to my phone (Samsung S21 FE 5G) simply by plugging in the cable and allowing the connection. Today, it didn't work. The phone filesystem is recognized on the ubuntu machine, I can mount the volume and peruse the filesystem, but I cannot transfer any files; the destination folder is created, but the file transfer locks up after 12 bytes. I cannot cleanly exit the file manager on the ubuntu machine; I have to "xkill" the window. Nor can I cleanly umount the phone filesystem; I need to rudely "pull the plug."
N.B. I have now tried this on three different computers (ubuntu-22, Almalinux-9.2, Windows-10) and several different cables, and multiple reboots, with no joy. What's going on? I do note that since the last time I successfully transferred music files to the phone, a software update has been applied: "One UI v6.0 Current version G990U3UEU7FL2/G990U3U7FL2, Security patch level: December 1, 2023"
Never mind. I seem to have found the cause and the solution. The filenames I was attempting to transfer contained an "illegal character" that caused the transfer to fail. By deleting that character from the filenames, the transfer worked as before.
