A search on Internet comes up with several suggestions:
- Install gvfs or kio-client, (Arch Linux Wiki)
- Switch from Dolphin to Thunar, or (Unsolicited but Offered)
- Boot your PC with Lumia connected. (Ask Ubuntu)
These methods work for some people but are not always successful. Here is another technique if you are unable to transfer files between your Lumia and Linux PC despite trying out every other method you have found so far.
1. Go to Windows Store and install Files, a file manager created by Microsoft Corporation. (The first app in the image.)
2. Connect your Lumia to your Linux PC and you will see it has been detected.
NOTE: You may see only Phone if there is no external (SD) card in your device.
3. Transfer files.
Common Issues1. Lumia is not detected.
Solution: Wait for five minutes. Or, try inserting the cable into a different USB slot.
2. I just transferred a bunch of MP3s but they are not visible in Music.
For some reason, you can only view transferred MP3s, images, videos, and other data in Files. Other apps do not detect them.
Did this technique work for you? Did you face other issues?
Kindly share your answers in Comments.