Arduino Pro Micro clone not recognized, flickering RX LED I have an Arduino Pro Micro clone that seems to be in some sort of reset loop. The RX LED is flickering very fast and very dim. The power LED also seems to flicker at the same frequency but has normal brightness.

The Arduino is not recognized by the PC at all anymore. It was working fine before. It doesn't matter if I try to go into the bootloader, by pressing reset twice, or not. Nothing happens. It feels like it is constantly resetting. The flickering stops if the reset pin stays connected to GND.

Another clone from the same shipment is still working fine. Both running the blink sketch. Just this one started to malfunction all of the sudden - after probing the pin I set in the blink sketch with my multimeter to see if the flashing was a success.
If your pro micro does not have a reset button, wire one between reset and ground. 

Press reset twice, quickly, and immediately hit upload on the IDE.

Secondly, make sure you've downloaded and installed the Sparkfun board files for the pro micro.