It doesn't appear to be a phone issue, but rather a PC issue.
If I try to copy any files larger than say 60KB (yes, kilobytes) via Windows, via USB, onto my Note 20, it doesn't get copied. The transfer just hangs, then the window disappears.
I have then tried another Windows computer, and transferring files larger than 60KB works great, without any problems. I have tried different files, USB cables, etc., but that didn't make a difference.
There is a SD card in the phone and even if I try copying direct to it, from my Windows 10 PC, I get the same problem.
My old Note 9 has no problems in receiving files larger than 60KB via USB.
If I try via Bluetooth, file transfer works great, but BT is incredibly sloooow.
Any suggestions? Thank you.
This is what the dialogue box looks like:
