Galaxy S7 can't reboot. E:failed to mount /system (Invalid argument) I got a brand new Verizon(unlocked) Galaxy S7 with Marshmallow on it. Tried to upgrade to Nougat using Smart Switch which got stuck at 36% for hours. Had to unplug and plug back back for recovery but in vain (my device didn't show up in Emergency Recovery).
I went into recovery mode and wiped cache and Factory reset but no use. My device refused to boot.

At the top of recovery screen, I see this

Verizon/heroqltevzw/heroqltevzw
7.0/NRD90M/G930VVRU4BQH4


And, at the bottom, below Error:

No Support SINGLE-SKU
dm-verify API: 3
E:failed to mount /system (Invalid argument)


Is there any way to fix it?
This happens because the system partition is damaged/corrupted. 

You should now flash the phone with Odin if using Windows computer or Heindal on a Mac. 

Download the firmware manually from the internet then flash your phone in Download Mode (Volume down + power button).  Also download Samsung USB drivers (Windows).