This is a monor problem, but intractable. In my administrator user identity, all sound schemes work, and all sounds play from the sound icon in CP. All sounds play during normal operation. However, at log-on/off, no sounds play even though the scheme shows correct in the registry. As a diagnostic, I created another administrator identity with the same permissions, and the log-on/off sound scheme played as it should. As a further diagnostic I have been running Regedit32 with both user hives (HKU) open, so I could compare settings for both administrator accounts, but no likely candidates yet. I have been making the test account systematically closer to the normal account, in the hope that it would eventually fail in the same way, revealing the errant key, but no luck yet. I have also run the compare function (in REG.EXE)between the two user/administrator accounts, with no obvious differences that would explain this anomaly. It recurs with every log-on/off; I log on in my usual administrator role and no log-on/off sound, and then my alter-ego identity logs on with normal sound events. This is W2kSP2 on a 850 MHZ dual processor machine (self-constructed) with 1 GB RAM. Any ideas as to what registry key I should check-out/reinstall? I'm assuming it has to be in the HKU branch, and not HKLM.