@solely yep! it checks the integrity (hash i believe?) of windows system files and compares them to its own database of what they should be. if one is wrong then the file gets replaced with a copy from its local store of compressed install files. it doesnt always work but its a good first step when troubleshooting because if a random system file is corrupt youre gonna have a bad time debugging the issue another way
https://en.m.wikipedia.org/wiki/System_File_Checker