Thumbnails in Bridge Downloader

I am using Windows 10 64 bit on a PC. I pay the monthly subscription to Adobe so I have all of the latest updates.  I have bought a Canon 1DX Mark111 and just received the Promotional SanDisk CFexpress Card Reader.  It comes with a cable, type C to C but I do not have a C port on my PC.  I bought a Hama cable C to USB 3.1 and I used this to connect the Reader to the PC.  I selected 'Download using Bridge CC' and the Adobe Downloader opened.  This showed rectangular thumbnails for each of my photos, together with their respective file names, but you could not see the actual images.  Each rectangle just showed a pattern of a painted flower.  I clicked 'Get Media' and the download was successful, in that the images did reach the PC but Bridge did not open automatically.  I had to go in manually.  In Bridge Preferences, File Type Association, the cr3 files are referred to and Photoshop 21.1 is shown as the associated program.  Does anyone know the answer to this problem as I would like to be able to view my images in the Downloader Dialogue so that I can decide which ones to leave out.  Help would be very much appreciated.