Mac M2 Photos not opening all RAW files thumbnail preview with Ventura. It will open some, but not all. All taken with same camera.

I think I've found the problem. I was able to 'open' the blank RAW files in a trial version I have an app called RAW Power (in the App store). I had to clik on each one and then it would open a preview of the image. In trying to use the RAW Power edit function, I got an error message that those raw files are compressed and apparently Apple's raw converter for Photos will not open a compressed image file. Then found a list of raw files Apple supports which notes Apple does not support compressed raw files.

I had shot those trying out the cRAW (compressed Raw) option on the Canon R8. If you want to save card or disk space Its an 'inconvenient feature' of Apple Photos and RAW Power. But at least I now know, and will not use that in-camera setting. RAW Power appears to be very good 'option' as it appears to be a good improvement on the organizing 'look' of the previews -albums etc. and far more processing editing options. It opened with all the new Photos albums I had been working on. Its developer was the developer of Aperture and it looks more like Aperture - which I sorely miss - then anything else like Photos -and opens those files Photos wouldn't even give me a clue about.

At the bottom of the list is this note. On another similar page RAW Power had linked, the same note specifically has the Canon and some other compressed c-raw as not supported.

1. Canon RAW format only

2. Uncompressed RAW format only

3. Excluding RAW images taken using High Res Shot

4. Single shot RAW format only

5. Lossless RAW format only

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I've had no problem with Photos (Monterey or Sonoma) opening the 'normal' uncompressed RAW from Canon CR3 files and showing the previews instantly. It was 50 or 60 pics I had shot trying the cRAW format which didn't open and just appeared 'something' was there but it was blank - did not show any preview even slowly.

The camera is a Canon R8, which is on the list. Other pics from it show in the preview ok.

There are about 50 ( I haven’t counted). I am importing several hundred from the memory card into Photos and grouping into Photos albums. They import fine when using an M1 with Monterey.