The problem appears to be intermittent... My thoughts were exactly the same as yours, but I've done these things time and time again to no avail. Since our domain controllers are also are Kix RPC servers, I've verified that the service is running on all of these servers is the appropriate version, and the service account tied to the RPC service is the same (it's is a domain admin account.) Additionally, I also set an environment variable called %LOGONSERVER% (with WINSET.EXE) on my 9x systems to see what DC/Kix RPC server authenticated that particular system. Every DC/Kix RPC server that has been stored in this environment variable, on a problem system, is running the Kix RPC service correctly. Regarding synchronization...I never have had any synchronization issues before with our current methods. My belief is that RPC requests made by Windows 9x systems are failing to reach the RPC server due to physical network issues. Many of the Kix errors I'm seeing in the Kixtart.log file appear to be timeout related. I'm wondering if anyone can cite specific examples of this in a switched network, where the physical network affected the Win 9x RPC faculties.