Hello, I installed C166 V6.00a over my old V.504, (logged in as Administrator) , got a new LIC from Keil, tried to compile a larger project and everything worked fine. I usually work on my XP Home SP2 with a restricted user account, not as an Admin. So when I log into my restricted account and compile the same project as before, I get the following warning C500 LICENCE ERROR (R208: RENEW LIC) on every module compiling. I checked the registry rights of HKLM/System and HKLM/Software, which are set to 'read allowed'. I temporary changed the restricted account to an Admin-account, but the error remain. Login with AdminAccount from which V6.00 was installed : Compiler works without error. Now I reinstalled my old V5.04 and everything is ok for now, saying I can work with my restricted account as before. Perhaps anyone has an idea what's going wrong there ? TIA (and sorry for bad english) Robert