Welcome to the forum Jarmila,
Do you get any messages pop up, if so screenshot them and upload here.
Which RAW file is it CRW CR2 CR3?
Which camera are you using?
Do you have an example file you can upload so that someone on Catalina can test.
Until a solution is found, you could convert the file to a DNG file, using Adobe DNG Converter: https://helpx.adobe.com/uk/photoshop/using/adobe-dng-converter.html
Hi jarmila,
Welcome to the forums
Updating to Catalina shouldn't remove any camera support from Affinity Photo - could you please confirm the camera model your CR RAW file is originating from? Thanks in advance!