Après application de la super résolution, PS couvre bien un CR3 + SR provenant du R3 mais pas du R5 mark II. J'ai le message impossble d'ouvrir, module de format de fichier ne peut interpreter le fichier

I would try the updated 18.3 Camera Raw plugin which has worked for other users with a similar issue:

https://community.adobe.com/bug-reports-562/p-acr-18-3-is-unusable-unless-you-disable-gpu-acceleration-1558055/index2.html

scroll on the way down to where it says show more replies and after clicking it’s in the yellow field.

I’m confused about “CR3+SR” -- is this proprietary to the Canon R5 MkII?

Try to say in english. PS opens without problem a CR3 file with super resolution coming from R3 camera, but not the CR3 + super resolution coming from the R5 mark II. CR and PS latest version

For some reason, the Translate tool here in Community did not translate the text of the popup into English.

It is: “Unable to open ‘_CDU8636. CR3’ because the file format module cannot interpret the file.”

Have you successfully opened file that are concatenated with a leading underscore?

[my wild guess was wrong]

Is this the first time you’ve imported an R5 file?