Slow / freezing importing

Trying to import from memory card to LR. 4000 images on card from a weekend shoot. All large 45 mb files from Canon R5. Not had this issue before. Not doing anything diffently than my normal workflow. Select my folder and have Copy set as my import option as I always do but after hitting the Import icon the screen just says importing images but nothing happens. Progress bar sits at 0%. I've left it for a good hr and still nothing.