I have been unable to access a group of photographs I took with a canon M50 which uses CR3 files. I am now using version 8 of LR Classic CC (so I think the CR3 issue has been a red herring.) I can see the photographs listed in my catalogue but see this. I have also included a copy of the finder folder where the files are stored on an external drive. Not sure how to get LR to recognize these photographs. Of note, the other files in the 2018 folder which as CR2 files are readable. Another possible red herring, the files have this icon.