Win2012 R2 Boot Configuration Data is missing

The Boot Configuration Data for your PC is missing or contains errors.

**
We have two options to solve this issue:

1.Run Startup Repair.
2.Rebuild the BCD file via the Bootrec.exe tool. **

Run Startup Repair

Steps

•Power off the VM.
• From left side,go to VM Settings >Hardware tab > CD/DVD > browse.
•Locate the Windows Server 2012 R2 media (ISO/DVD).
Note: It should be the same Windows Version that already installed.

Set the default boot device to CD/DVD as the following: ◦Power on VM > Press F2 to open Bios Setup > Boot Menu > Select CD-ROM Drive and Press + to go up and - to go down.
Press F10 to save and exit.

•The VM will be rebooted with the default option CD/DVD.
•Press any key to boot from the CD/DVD.
•At the Windows Setup Dialog,set your appropriate settings > click Next.
•Click Repair your Computer > Troubleshoot > Command Prompt.
•Navigate to the recovery folder by typing cd recovery > press Enter.
•Run Startup repair by typing startrep.exe.
•Wait until the repair finished.

Unfortunately,in this case,the startup repair Couldn't repair the issue! so we will try to Rebuild the BCD file via the Bootrec.exe tool.

Rebuild the BCD file via the Bootrec.exe Tool

Steps
•Again,click Repair your Computer > Troubleshoot > Command Prompt.
•Type the below command to rebuild he Bcd file.

bootrec /RebuildBcd

•Once the operation completed successfully > close the command prompt.
•Click Continue to Exit and continue to Windows Server 2012.
•The Bcd file should be Now rebuilt and the Windows should be working properly.

https://social.technet.microsoft.com/wiki/contents/articles/40265.windows-server-2012-the-boot-configuration-data-for-your-pc-is-missing-or-contains-errors.aspx