I just "upgraded" from a Canon 6D to a 5D Mk. IV. Its RAW (CR2) files will no longer preview as image thumbnails in either Microsoft Windows Explorer or in Photoshop CC. The only way I can see them is to open them in ACR. This was not a problem with RAW files from the 6D. I have the latest updates to Windows 10 and Photoshop. I'm looking for a quick and easy way to view groups of thumbnails all at once, of reasonable size, so I can quickly decide which to delete and which to open in ACR and PS to edit. How do others do that? (I couldn't find workable solutions on Microsoft or Adobe forums.) Thanks much.