Hi, I have a WavePCI WHQL Certified under 12.1 HCT that works perfectly under XP in all situations. Under Win2k, however, I am seeing the following: 1. Using the AUDIO_CAPTURE filter in GraphEdit does not work. Specifically, I see three things that are bad: A. Only one call to GetPosition() happens to my driver from PortCls; B. GetMapping() always returns "no mapping available" and; C. When I press Stop in GraphEdt, GraphEdt locks up and I must reboot. When I look in the kernel debugger, I see that all threads in GraphEdit are "BLOCKED". I think that the threads that are supposed call GetPosition and that are supposed return mappings to my driver are blocked waiting for some (very important) event. I think that (B) is caused by a lack of GetPosition() calls. 2. Using the "WDM Streaming Filter", everything is perfect as in XP. 3. Using SoundRecorder (which uses WaveAPI) I see all the same behaviour as in (1) above, except that I am able to stop the stream (which is not moving) and close SoundRecorder properly. I have made sure my driver is calling Notify() properly.not too often and not too infrequently. There is no CPU overload issue. I am using Win2K SP4 with all the latest updates. AUDIO_CAPTURE is created by QCap.dll which uses Wave API. Sound Recorder uses Wave API. Those both fail in similar ways. "WDM Streaming Filter" uses KxProxy. That works. Of course, my driver has no idea whether KxProxy or QCap.dll is in play.the same code paths happen. Has anybody seen such behavior have any idea what could be wrong.? Thank you for your time. ****************** 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/