Has anyone seen this before? I'm guessing the autoexec.bat file is looking for the executable on the wrong drive path. Is there a way to manually force the program to run, or is my USB creation method the problem?

rather than AHCI if the DOS environment fails to "see" the drive or the files on it. Important Considerations for Hard Drive Health

It is most commonly run from a bootable environment (DOS or WinPE) because you cannot repair the system drive (usually C:) while Windows is actively using it.

command shows an empty list or doesn't show the regenerator file, your bootable media likely failed during creation. HDD Regenerator software on a working Windows PC. Bootable USB Flash Bootable CD/DVD Let the program format and re-write the files. HDD Regenerator 3. Use the Correct Command