Master Boot Record (MBR) is the data stored on the first sector of the storage drive that locates and loads Windows. If you’re getting different errors like ‘Operating System Not Found’, ‘Missing Operating System’, ‘Invalid Partition Table’, ‘Bootmgr is missing’, etc., these all could mean that the MBR is probably corrupted.
When this happens, you’re likely going to face boot problems. There’s no fixed reason why the MBR could get corrupted. But usually, this is due toimproper shutdownsandransomware attacks.
Fortunately, it’s possible to troubleshoot this problem using theBootrec.exe utilityor bycompletely rebuilding the BCD. Here are some troubleshooting tips that you can try to fix MBR on Windows.
Perform Startup Repair
Before anything else, I recommend performing startup repair. This is a built-in Windows feature that lets you fix any issues that may be failing your OS to boot up. You can access this from theWindows Recovery Environment/Advanced Startup.
Note:If your PC doesn’t get to the Windows Recovery Environment after performing a hard reset, you need to insert a bootable disc or flash drive. Then, from the Windows Setup screen, pick ‘Repair my computer.’
Repair Critical Disk Structures Using Bootrec.exe
Startup Repair is just a general fix andmight not workfor the majority. On the other hand, Bootrec.exe is a specialized utility that can repair the MBR, boot sector, and BCD Store. Executing the dedicated commands can help fix the corruption issues and update the MBR code.
Complete Rebuild of BCD Store
In most cases, a simple rebuild of the BCD store should fix the MBR. However, if you’re getting the‘Bootmgr is Missing’error, the solution above might not be enough. In that case, I recommend backing up your BCD store first. Then, delete it and rebuild the BCD store as instructed below:
Perform System Restore
If neither of the two methods solved your problem, I recommend opting for System Restore. This should take your Windows back to a working configuration based on the specified restore point.
Clean Install Windows
The last option is to reinstall Windows. When you clean install the OS, both the corrupted MBR and boot sector will be replaced.
Before proceeding to perform a clean installation. make sure you havebacked up all your important files. I understand you can’t boot into Windows right now. But there are plenty of solutions available on the web. I personally recommend removing the storage drive and cloning it to another one for the time being.
