If you remove the right hand extruder then you lose the ability to stop the X axis, which can result in the belts skipping and any sort of problem.
Print this dummy extruder to be placed where the original one was, reuse the fan and bolts and spacers but can omit the black aluminium heatsink.

If you're wondering why would one remove an extruder? In my case, I print a few things with PETG, which strings quite a bit and very often I'd get the unused extruder (the left, I'll explain below) to touch the part that's being printed. This is usually not a problem with PLA, but it was with PETG, at the point that most of the printed parts would show deformation or flaws in their bottom-left corner.
Rather than fiddling around with settings that may not resolve the problem, it was much easier to remove the right hand nozzle and extruder.

Another reason to remove the second exttruder is the reduced mass moving in the gantry, which is a good thing.
I wasn't using the two extruders at the same time during a print, I would usually keep the left extruder with PLA (because needs cooling, and the fan duct is right there) and the right extruder with PETG.
I could have removed the left extruder and nozzle, but this means that printing with PLA from the only nozzle left, will result in very poor cooling since the fan duct is far away.