i have 5 u2 and my winxp detect only 3 but when connect to win8 it detect all 5, i think its OS problem, likely OS dont support the driver? (sorry mine U2 donno if it's U2+ maybe problem related :p) winxp is 32bit win8 is 64bit bgfminer 64bit for win8 and bfgminer32bit for xp

in xp when 3 stick plugin all port id show ok but when plugin 4th miner, the 4th port id show error.