nRF52840-preview-DK shows no JLINK folder when connected to a PC

[jyang]

I have connected the board to a PC and it prompted a JLINK folder when connected to a PC. However, when I tried an example project on the IAR workbench, I think I clicked the debug button and flash the code to nRF52840-preview-DK. After that, when I connect the board to the PC, the JLINK folder has never come out. 

When I press the reset button and insert the USB connector, a bootloader folder will appear on the PC.

How can I get the JLINK folder back

[jyang]

It seems that when I put a bin file to the bootloader folder, it removed the J-LINK OB. I downloaded a J-LINK OB bin file and put it into the bootloader folder. I can see JLINK folder now.