You need to define APPDATA and USERPROFILE environment variables.CharlesF , we need you help. The printer drivers you have are old and most likely can't be affected by KernelEx. Crash you had happens in spool32 which is excluded from KernelEx. There were no core changes between RC4 and RC5 either. Please elaborate on your problem: * does problem occurs with KernelEx installed in 'disable by default' mode? * how bad is hang and what it seems to be caused from (message loop, high cpu usage, i/o, windows drawing, etc) * does problem happen with spoolss.dll from winme? * if you decide problem is surely RC5 specific, try RC5 with kernelex.dll from RC4.