@homer hi! Thanks for responding. Unlocking the screen didn't make any difference, the phone just charges without registering on my laptop.

I have Ubuntu Touch installed on a Fairphone 4. Now I want to transfer pictures, ebooks and MP3 files from my computer to the phone, but Linux Mint won't recognise and mount the phone as a filesystem. USB cable is new and charges the phone fine, and I used the same laptop running Mint to install Ubuntu Touch onto my phone. Developer mode is on. How can I get it to recognise, and allow file transfer?

The issue appears to be Ubuntu Touch since the PC recognises an Android just fine and I have done frequent phone clearouts previously.

Thank you!