Thanks for response. Ok this is what happens...
I connect the cardreader with card to the USB drive to open up in Windows Explorer. I get the message "There is a problem with the Drive scan and repair" which I do and them the cardreader will work and open up in Explorer.
If I do the same procedure with Photo Mechanic set as open in autoplay, it opens with the Ingest screen ready to go, however when I click ingest, either none or the first two photo files will load after a considerable time and then the process stalls.
I also have a Sony XQD card reader that has no such problems. It recognises and downloads files quite quickly, despite having 2.0 USB drive and also 3.0 USB drive.