kink
technical difficulty
pressure point
hard-set
a bad penny always turns up
wrinkle
enmesh
miscompose
wicked problem
precrack
interference
weakest link
gum
preventive
hinderance
preventative
incumbrance
if we had ham we could have ham and eggs, if we had eggs
hindrance
throw a wrench in
crab
encumbrance
hitch
fight a losing battle
trouble
fractious
goof up
catch a cold
unstabilize
disable
difficultate
block off
mislaunch
goat rope
problem
stonewall
do-or-die
maloperation
put a hurt on
hair trigger
fuster
gotcha
handful
teething troubles
no-win situation
hit a wall
give someone a hard time
entangle
huck
be riding for a fall
sterilize
counterdifficulty
master key
bungle
escape fire
hinder
obstructive
Matterhorn
look for trouble
destabilise
get into trouble
destabilize
killer
race condition
burn-in
sow dragon's teeth
crisis
snag
panic
self-defeating
break down
off the rails
recalcitrant
throw back
obstacle
second best
postlapsarian
mismanufacture
bring off
the jug goes to the well until it breaks
debugging
flaw
P-complete
incompetency
dead duck
undermaintain
conflict
hard nut to crack
disorder
enterprise
tough nut to crack
bulletproof
rear one's head