Q: nRF52840 DK does not appear as a removable drive named "JLINK"

[ramsringar]

Q: nRF52840 DK does not appear as a removable drive named "JLINK" 
Steps I followed
1-Connected the NFC antenna to the board.
2-Used a micro USB 2.0 Data cable(Fully functional and tested) to connect the nRF52840 DK to one of your PC's USB port.
3-LED 1 has started pulsating
4-buttons SW1 to SW4 LEDs are pulsating.
5-No removable drive named "JLINK" appeared on my computer(windows 10)
6-Tried BOOTLOADER mode....nothing appeared on my computer(windows 10)
7-NFC enabled phone prompt to open a URL near NFC antenna. (Success)
8-Tried with two more USB data cables.(to appear "JLINK")...Nothing happened
9-Tried with 2 more windows 10 computers..no result
10-Trying to resolve the issue since 9-10 days. Please help!

[haakonsh]

My first guess is a faulty J-link driver. 

I suggest you use the following CMD command: nrfjprog -f nrf52 -e

This will find any jlink thats connected to a nrf52 device and do an erase all operation on the connected nrf52. 

My second guess is incorrect settings of the various switches on the DK. What are the states of your switches? And what is the voltage of VDD?

[ramsringar]

SW9: VDD Mode, SW6: Default

[haakonsh]

That looks alright. Any luck with nrfjprog?

[ramsringar]

no luck

 "J-Link Commander", executed command: msdenable

Result: Probe configured successfully

Turned board off and on.......NO JLINK appeared.

tried bootloader mode too....no result.

[ramsringar]

No reply Sir?

[ramsringar]

Tried nrfjprog -f nrf52 -e command....and -r reset....LED blinking stopped.

then msdenable from jlink commander...no result
Programmed new hex file...Led started blinking
But JLINK drive not appearing on my computer.
Tried jlink driver version: JLink_V640, JLink_V640b, JLink_V642

Please help!