Hello Jeff, > My recollection is that the original release of Vista didn't support event > notifications (or they didn't work properly) but that was fixed in SP1. PortCls Win7 does not support it for WaveRT drivers. So I'm afraid it would be better to not use KSEVENTSETID_LoopedStreaming at all. For STANDARD_STREAMING with KS_READ/KS_WRITE, an event can be specified in OVERLAPPED structure and for STANDARD_LOOPED_STREAMING with RTAudio, polling works nicely. Regards, Eugene ****************** WDMAUDIODEV addresses: Post message: mailto:wdmaudiodev@xxxxxxxxxxxxx Subscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=subscribe Unsubscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=unsubscribe Moderator: mailto:wdmaudiodev-moderators@xxxxxxxxxxxxx URL to WDMAUDIODEV page: http://www.wdmaudiodev.com/