What do I have to do to get Windows 10's File Explorer to show me thumbnails for CR2 files generated by my EOS M5? It has no problem showing thumbnails for CR2 files from my EOS-60D.
WIndows 10 did not ship with raw support native. You may have a canon driver installed that is allowing the previews if they are showing up, are some other image program that supports the 60d. There is a Win10 download called raw image extension that may help you. But honestly I never have bothered with it, over the last 2 decades I have always worked with the Canon supplied software or Lightroom for file management and not relied on the folder to preview the raw files.