It seems that the last version of CGMiner that could find all 5 of my USB Erupters immidiately on every start is 3.6.4
Any newer version of program finds randomly 0 to 5 devices. Sometimes it happens certain device is not found even
after few hours. What exactly is changed after version 3.6.4 that affects USB Erupter detection? Im using Win7 64-bit
but issue exists with WinXP 32-bit as well.
3.9.0 finds all 22 of my BEs within a minute or two on restart pretty reliably (win7 i3 box using powered 7-port USB2 hubs and an fan to keep them cool). I also am running cgminer 3.3.1 to mine scrypt on a gpu (it doesn't see my BEs), and cpuminer using just 2 threads mining a cpu-only coin just to keep from wasting available cpu cycles

(I found cgminer had problems managing the BEs if I used more cpu threads mining). I have 4 antminer U1s running on another machine using a forked version of cgminer since they don't play well with BEs at the current software level of maturity (they are a relatively new device that unfortunately share the same USB ID as the BEs, but the 4 are as fast as my 22 BEs!).
Bottom line - I've had good luck with the newer versions of cgminer - great devs!