Sometimes when I wake up after playing the last day I simply can't open my inventory when clicking I key. It's happened a few times and the only solution is restarting the game.
But I've been loving the game and can't wait for new content. :)
#Can't open inventory with I key
tender solar
astral mauve
desert raptor
Go outside or use a chest, that usually works for me
gray sinew
Please, if it happens again send us the player.log file