I tried backing up the boot drive of an older Dell Inspiron and restoring it to a new Dell Inspiron 3020 but the new Dell UEFI BIOS doesn’t support booting from an MBR. The solution is to convert the hard drive from MBR to GPT.

Steps to convert MBR to GPT.
1. Restored the backup of old Dell to an M.2 drive and put it in a computer that supports MBR.
2. Booted from a USB drive with Windows 11.
3. Opened Command Prompt
4. Run Diskpart and see what is the drive number is of the M.2 drive
5. Go to windows\system32 and run mbr2gpt /validate /disk:x (where x is the drive #)
6. If validation is successful then run mbr2gpt /convert /disk:x (where x is the drive #)
7. Installed the M.2 drive in the new Dell computer.
8. In the UEFI BIOS of the new Dell computer I change the following 2 items. I am not sure if they were all necessary (1. changed RAID to AHCI/NVMe. 2. turned off Secure boot.)

Errors

https://learn.microsoft.com/en-us/windows/deployment/mbr-to-gpt

Four log files are created by the MBR2GPT tool:

• diagerr.xml
• diagwrn.xml
• setupact.log
• setuperr.log

These files contain errors and warnings encountered during disk validation and conversion. Information in these files can be helpful in diagnosing problems with the tool. The setupact.log and setuperr.log files have the most detailed information about disk layouts, processes, and other information pertaining to disk validation and conversion.