WL7 tracks overdistorted after rendering

since yesterday my WL7 has a strange behaviour, well i think i did something wrong … when i try to master my tracks
sound on WL7 quit good but after the rendering when i hear it on itunes sound overdistorted i mean sounds very baaaad !! loudness on average -10db in WL sounds very clean and clear after rendering sounds overdistorted
maybe can somebody tell me what im doing wrong this will be a big help for me !!!
thank you :slight_smile: