It has been reported by other peopole as well in the forum that mtp device file transfer doesn’t work,
“an unexpected error occurred during operation”
It seems to be a problem of KDE, I find the fix in the Arch linux wiki:
"If you are not able to use the action “Open with File Manager”, you may work around this problem by editing the file /usr/share/apps/solid/actions/solid_mtp.desktop
Change the line
Exec=kioclient exec mtp:udi=%i/
To
Exec=dolphin "mtp:/"
"
For me the path is /usr/share/**kde4/**apps/solid/actions/solid_mtp.desktop
I’m not a developer, but the UDI refers to the specific device identifier passed from Solid device notifier. Pure speculation on my part, but I guess the more generic mtp:/ handler is used to get a list of attached MTP devices. Maybe it is a timing thing - I sometimes have issues if I try to view photos from my camera via MTP if I don’t wait sufficient time for the initialisation process to complete.
I have not had any problems transferring files between my Desktop and Android device using Dolphin with the original settings (accurately described in your first post).
Although I can’t be certain, in general whenever I see something which starts with or has “kio” in the name I assume it is related to “kernel I/O”
It also looks like although there is no man page, a help file does exist
kioclient --help
So,
I would wonder, getting back to basics, when you connect your mobile device, then open Dolphin manually… Do you see the device automatically detected and listed in the “Devices” pane on the left?
If you do, then click on the “Split” button on the top (although awhile back Dolphin fixed a problem drag and dropping between windows but I continue to distrust that. I highly recommend drag and dropping between split panes instead).
Then click on the mobile device in the Devices pane to list and view the file structure of the mobile device.
Thne drag and drop (or copy/paste) from one pane to another.
If you have the time and are willing to revert back to the original setting and test the procedure I described, it might provide clues what and where something might be not owrking.
If I remember right, the issue was that I didn’t have the write permission on the nexus 10 that’s using mtp. (My android phones works well) But the nexus 10 can be detected perfectly well.
On Ubuntu I don’t have this issue, on Fedora KDE i had this issue too.
And after I used the solution above, the problem was solved.