Recover backup files

I have backed up my personal PC for years with Comodo Backup and did not realize that it was discontinued. Eventually, my PC crashed and now I need to access the backup files that are on an offline disk. I’ve downloaded a copy of the unsupported software multiple times and each time I received boot errors. With a lot of troubleshooting, I was able to fix the boot errors. Can anyone provide some insight on how to avoid the boot errors or otherwise access the .cbu backup files. Thanks.