MacBook Pro Late 2013 unable to write to ANY external media
My MacBook Pro, Late 2013, is unable to write to ANY external media. Anything that is plugged in (by which I mean SD cards or USB drives) comes up on the desktop, I can read file contents, but cannot write. No matter which port I plug it into.
I have tried the media on other (various) devices (iMac, MacBook Air & another Pro) and it works everywhere.
I have created a new user, and tried there- no luck.
I have tried to alter permissions on the drives, but they say I should be able to read AND write.