Black screen with the letter "J" after cloning a drive

WORKED SOLUTION: I had also the same error blinking letter "J" with the tool MiniTool Partition Wizard. What helped was performing an extra step in MiniToolPartition Wizard. Click on new SSD Disk, went to menu "Disk" --> "Rebuild MBR" (on new disk) --> Apply. Afther that new SSD disk was recognized when booting to Windows 10.

firstcomputersv said:

It won't matter what type of drive it is SSD or mechanical I have tried both types when cloning and on 2 different Asus motherboards the drives boot to a J.
The only fix I found was boot to command prompt and use diskpart. The letters are usually swapped system reserve is c and main is d. You have to swap them back.
diskpart - to see the drives
list volume - to see and chose the partitions
select volume - to make changes to that particular partition
remove letter=C to remove the wrong letter C from "system reserved" partition 99-100MB
assign letter=k or whatever is available, then select volume for main partition
remove letter=d or whatever letter the main partition is (usually the largest partition)
assign letter=C
list volumes to double check that it is now correct
exit stay in command prompt and perform the following commands
enter cd C:\windows\system32 hit enter
bootrec /fixmbr hit enter
bootrec /rebuildbcd hit enter
exit
boot to windows
Hope this works for you please let me know if you have any questions.

This solution actually helped! Thank U!