> This is on a > G4 533/DP > 640meg > LAMP 5.1.3 > System 9.1 (is this the culprit?) Yes, I believe it is. My "old" 533DP was horrible in regards to USB midi until I updated to 9.2.x, and used Conflict Catcher to move OMS to the top of the load order list. Haven't had a single midi USB error since (6, 7, 8 months?). Even if you don't use OMS, updating to 9.2.2 is certainly an excellent thing to try. best, Jon --config-- Apple Dual 800 G4, 1.5 gigs ram, Mac OS 9.2.2, RME Hammerfall DSP, MOTU 2408, MOTU MTP AV (USB), OMS 2.3.8, Spirit 328 Digital Mixer/Controller, Apogee Converters (WC Master), ATI Radeon AGP, ATI Rage 128 (second monitor).