Bridge stop showing thumbnails of Canon & Nikon RAW files

Why has Bridge 12.0.3.270 suddenly stopped displaying thumbnails for my Canon CR3, Nikon NEF RAW files, and TIFF Files. Displaying JPEG and MOV has no problem. Win 10 64 Bit operating system.  I have reset Bridge Preferences but it still doesn't work.  I also uninstalled Bridge but it behaves the same.  Please help !