hashcat keeps stopping itself and I don't know why.

[philsmd]

I have no warning and I have not set fan speed

you say that you don't see any warning but at the same time you post a screenshot ( http://imgur.com/a/mNKP5 ) that displays the error message:

ERROR: Temperature limit on GPU 2 reached, aborting...

Well, actually you are right, it's not a warning but it's an error message. Anyway you just need to pay attention to what the output says. It should be very clear.

What you should do is: improve cooling (including the investment in better/additional case fans) and/or try to play around with setting GPU fan to 100%, maybe even try to underclock the GPU etc.... and of course if you have problem with cooling you shouldn't use -w 3. Instead, you should try w/ -w 1 (but of course it will decrease performance).