What is the reason that the boot system prompts boot.ini illegal?

Each time you start the system, you will be prompted that boot.ini is illegal. The system is booting from d:\\windows, and the system can be started normally. There is no problem with the use. Is this what is the reason?

This may be caused by improper operation when uninstalling the system after installing dual system or multiple systems. For example, manually editing the startup file boot.ini in the root directory of the C drive causes the file to contain errors. Detect the contents of the file and give a prompt after encountering the error.

Windows will automatically make a backup boot.ini.backup in the c:\\windows\\pps directory. Just copy the file directly and overwrite the file with the same name in the root directory of the C drive. However, before the operation, you need to set the file display property to "Show all files" and "Show the contents of the system file" in the Explorer via the "Tools/Folder Options" menu. Then find the backup file by searching function and remove it. After the .backup suffix, copy it to the root directory of the C drive to solve the problem.