But Adobe created an open-source digital negative format called DNG. A DNG is a RAW photo file but, because it is open-source, DNG is widely compatible with a number of different applications.

I tried re-converting the DNGs using Adobe DNG Converter with liinear mode turned off and they still wouldn't open.I might give it another go and see if ADC can convert the original .CRW files ...

DNG is an open format, and it's (possibly) more likely they will be viewable in the future. Export the photos as JPGs and delete the RAW files. Keep both RAW and exported JPGs. What do you guys think?

' RapidRAW ' is an open source RAW development app that supports non-destructive editing and is also advertised as being capable of high-speed processing using GPU acceleration. It looked useful ...