Could you make sure you are using latest version of Lightroom(check from Help>>Updates)
Please uncheck "Use graphics Processor" under Preferences>>Performance
Then,Restart Lightroom and try again
If that does not helps, Copy the images from Card to desktop in Explorer/Finder
Then import those images from Desktop in Lightroom
Let us know if that helps
It works if i import into File Explorer - thank you. Do i then have to export to my catalogue after importing into LR?
This means there is a an issue with Read/write permissions with your Card.
You do not have to export the pictures.It will work the same way as it worked with card.
It is a good practice to keep backing up Lightroom regularly.