Hello @XH !
Thank you for your interest in using MBDT!
It seems that the download can't be performed because the JLink.exe file is stored at a different address on your machine, as compared to the one saved in the Hardware Settings of the model. By default, the model has the following address stored for the JLink.exe:

It is very likely that the SEGGER folder and related files are stored in a different location on your machine.
Please open the Hardware Settings window of the model, and on the Download menu, select the correct path for the JLink.exe. The download issue should no longer be present afterwards.
Please let me know if this solves your issue and if you need additional help.
Best regards,
Florin.