I am having several problems with removable media this week. A 64GB card will not mount after I accidentally pulled the card reader's lead out of the USB port. So I started copying the files instead onto an old 32GB (FAT32) flash drive which became read-only as I'd almost finished. Not only that, but 'Properties' shows the current contents of the stick as 29GB but the files themselves show as 41GB.

I tried dmesg and check/repair filesystem on the flash drive but the check seemed to be hanging for several hours. I've no idea about the 64GB card - I tried it on a Windows PC and it doesn't even show up. I'm new to this and am really getting frustrated.