Problem reading SD card from my computer

[rstaveley]

I recently bought a new Nokia 3.1 running Android One. Concerned at the small amount of internal memory I bought a SanDisk 32gb SD card and decided to partition it so that half the card could be used as internal memory and half as portable memory, using ABD from my PC. That appeared to work fine, but when I try to access the SD card in the phone using a USB cable from my computer I have problems, The PC sees the card but cannot read anything on it (I have set the USB option to Transfer Files) and can't write to it. If I take the card out of my phone and put it into the SD card slot on my PC it reads fine.

Any suggestions would be gratefuily received.