You can’t do that manually, so to win them back, you should use special software. The sad thing is, MBR errors often come with data loss, which means you might need to recover your valuable files.
The easiest way to do that is by using the special installation Windows 10 disk.
This one is pretty straightforward: to resolve the issues in question, you should repair the Master boot record.
How to fix MBR errors without installation media in 2018?
They often crop up due to malware attacks or improper shutdowns. MBR errors occur when your Master boot record fails to work the way it is supposed to.