Windows Server 2012 R2 Boot Repair 【95% QUICK】

This occurs when the boot process fails twice consecutively. Windows tries to run Startup Repair repeatedly, fails, and loops.

Break the loop:

If the server begins to boot but crashes (e.g., during classpnp.sys or disk.sys loading), a third-party driver or service is likely the culprit. windows server 2012 r2 boot repair

Enter Safe Mode:

For virtual servers (Hyper-V, VMware):
Disable dynamic memory or integration services temporarily, as these can cause boot loops. This occurs when the boot process fails twice consecutively

A less common but tricky cause is a corrupt system registry hive. Windows keeps backups of the registry in the RegBack folder.

Steps:

cd d:\windows\system32\config

ren default default.old
ren sam sam.old
ren security security.old
ren software software.old
ren system system.old

copy d:\windows\system32\config\regback\default .
copy d:\windows\system32\config\regback\sam .
copy d:\windows\system32\config\regback\security .
copy d:\windows\system32\config\regback\software .
copy d:\windows\system32\config\regback\system .

This effectively rolls back your registry to a previous working state.

If boot files are intact but Windows hangs during boot: cd d:\windows\system32\config