We received a new case on customer’s Mac external hard disk that has dirty volume after restoring the entire hard disk drive. Customer restores the external hard disk to another hard disk by using MAC building software, and system prompt “Mac OS cannot repair the disk”.

Our engineer found the method to resolve the problem. By performing the first aid on the hard disk, but the operation failed. There is an error message states “File system check with exit code is 8”. Engineer then tries another method, by using software to read the hard disk partition. Edit sector in 409642, change the hexadecimal value to 80 00 39 52.

And we managed to success and system will not prompt the error message again.