Did StarBurn return you anything except EN_SUCCESS in it's CloseSession(...) API call? No? So what was the reason of looking at debug window text? It's information for RDS team and not for you... In general it's *NORMAL* for some of the SCSI commands queued to the device to complete with bad status in some particular cases. Right now we send async "close session" and then ping device with "disc info" and "test unit ready" until it would stop telling us "long write in progress" (exactly your case). This would mean end of long async operation. Successful end! So what you see should be interpreted as "not ready... not ready... not ready yet! Done!!!" That's all