Illustrator says .ai file is unknown format and can't be opened

Hi there. I'm struggling to access two of my old logo files. One says it is too damaged and can't be repaired, the other says it is an unknown format even though it is an .ai file. Is there any way to get these open?

Happy to send the files if that helps! But attached screen grabs.

I am using the most up to date CC software on Windows 10 if that helps. 

Thanks!