I shot .CR2 files on my Canon Rebel T7. Now I can't open the files in Lightroom 6. How can I convert the .CR2 files into a .RAW format?
Adobe does not support the Canon Rebel T7 in LR6, only in the newer Lightroom CC/Lightroom Classic CC. If you'd like to, you can convert your .CR2 files to .DNG files using Adobe's DNG Converter (DNG is an open format created by Adboe meant as a replacement for proprietary camera RAW formats).
Lightroom 6 will then read the DNG files as you would expect.
As of December 2017, Lightroom 6 is no longer supported. Please see this Adobe blog post for more information: http://blogs.adobe.com/lightroomjournal/2017/12/6-14-now-available-last-perpetual-update-of-lightroom.html