Windows Server 2012 R2 Boot Repair -

bootrec /fixmbr bootrec /fixboot bootrec /scanos bootrec /rebuildbcd If still failing, rewrite the entire boot sector:

bootsect /nt60 sys /mbr A corrupted SYSTEM registry hive breaks boot with errors like 0xc000021a or 0xc0000034 . The recovery environment allows you to replace it with a backup copy. windows server 2012 r2 boot repair

From Command Prompt:

Few IT scenarios induce as much immediate stress as a production server that refuses to start. When that server is running Windows Server 2012 R2—a workhorse operating system still powering countless domain controllers, file servers, and application hosts—boot failures can paralyze an entire organization. When that server is running Windows Server 2012

bcdedit /export C:\bcd_backup attrib C:\boot\bcd -s -h -r ren C:\boot\bcd bcd.old bootrec /rebuildbcd With the commands and techniques outlined in this

The most important takeaway is never to panic and never to format and reinstall as a first response. That last resort wipes configuration, roles, and data. With the commands and techniques outlined in this guide, you can repair the boot process on Windows Server 2012 R2 in 90% of cases without losing your server’s identity and data.

Sometimes bootrec /rebuildbcd fails with "Element not found." Use BCDEdit: