How To Run Startup Repair Windows Server 2012 R2

This commodity describes one of the many bachelor procedures for recovering a Windows 2022R2 server which is stuck in a kick loop. It will bear witness "Preparing automated repair".

I'm sharing this on LinkedIn and so everybody can observe it since I don't keep a blog or whatsoever. Some parts of the procedure are taken from other people, I've only mixed the ingredients and added the needed extras to get things working.

The boot loop occurs later i, or a combination, of the following scenarios:

Using VMWare vSphere
Migration of the VM
Replication of the VM
(Storage)VMotion of the VM
Recovery of the VM
Installation Windows Updates
VM is set to apply EFI

If ane of the above applies it can happen the server starts with "Recovery Mode" and basically nothing works.

Afterward following the regular recovery methods found on cyberspace things simply won't piece of work, at that place is something wrong with the bootloader and something else

Since some more testing the issues reoccurred and subsequently further investigation it appears storage hardware is involved likewise. Meet the bottom of the document for this best-practices. Check this out start to see if it applies to you, if information technology doesn't continue the procedures.

Outset of all, we demand to get rid of the boot loop process which we tin can do past executing the following procedure (there are more procedures but this 1 works for this scenario):

Boot loop repair

Boot WS2012R2 ISO, go out defaults and click Next
On the lesser left click "Repair your computer"
Choose Troubleshoot and then Command Prompt
Run diskpart
Type list vol
Locate the number of the modest FAT32 EFI-sectionalisation, in my case nr three
Blazon sel vol three
Blazon assign
Type list vol
Locate the letter of the alphabet assigned, in this case Due east:
Type leave
cd /d e:\efi\microsoft\boot
ren BCD BCD.bak
bcdboot c:\windows /l en-us /due south E: /f ALL
bootrec /fixmbr
bootrec /fixboot
bootrec /scanos
bootrec /rebuildbcd

Note that the scanos and rebuildbcd shows 0 plant Os.

Simply leave it every bit information technology is. Exit the Control prompt and select "Go along to start Server 2022"

Afterward that reboots two things can happen:

The server starts, problem solved
The server gives an error on a file missing similar NTOSKRNL.exe, go to the side by side chapter to fix this.

Fixing boot Error

The problem is located in the NTOSKRNL.exe file which is located on the C-Drive simply somehow is not working. We are going to look for a version before windows update and move it to this location.

Boot WS2012R2 ISO, leave defaults and click Next
On the bottom left click "Repair your computer"
Choose Troubleshoot and and then Control Prompt
Blazon C: and make sure you are in the root
Type dir ntoskrnl.exe /south and you lot will find multiple versions. We are going to replace the one below.

The one show higher up has a appointment of 01/01/2018, this was the verbal moment later recovering the VM to another server. Why is ntoskernel.exe changed on that date, no idea!

Scroll down and discover the proper file and note the location
Type cd \windows\system32
Blazon ren ntoskrnl.exe *.org
Copy the file from the noted location to c:\windows\system32

Blazon exit
Click proceed to reboot and the server should be starting again
Once booted and verifying the file we encounter the engagement has changed

Storage Hardware Verification

Afterward more testing, information technology is noticed that some storage vendors have issues while booting EFI VMs. For VMWare, this is the article: https://kb.vmware.com/southward/commodity/2137402

In this scenario, a PureStorage device is being used which also is worth the investigation. You will find their details here: http://info.purestorage.com/rs/225-USM-292/images/FlashArray%20VMware%20vSphere%20Best%20Practices.pdf

Execute the following steps on one host, this tin can be done on the wing.

Navigate to Host > Configuration
Click Advanced Settings
Navigate to Deejay
Alter the Disk.DiskMaxIOSize value to 4096

At present move a powered-off problem VM to this host and ability-on the VM. Surprisingly this seems to exist an issue besides.

Conclusion

Something goes awfully incorrect with VMWare VMs using EFI boot at an unexpected moment. The behaviour is near unexplainable since at that place are many fixes to observe on the internet but none of them come across to work 100%. Also reviewing all boot manager setting and references everything should work, just it doesn't…

It can happen after Windows Update, VMotion, Replication, Cloning, Restoring, Recovering or whatever combination of those. Merely the most important affair is that it is frustrating and it happens when y'all don't want it. It saved me re-installation of several servers.

The office concerning replacing the corrupt file is a possible cardinal to success for this scenario. All the same the PureStorage device was a big surprise as well! Of course, no warranties are issued on this procedure.

If you have any suggestion on the cause or how to prevent it just leave a comment. Also if it was helpful let others know!