I'm getting the compiler unable to open error about once a day now and have to reinstall MT4 to 'fix' it. It always shows up again at some point. My McAfee virus software found the MetaLang.exe trojan horse virus but can only move it to the quarantine folder, not clean or delete it. Every time I try to reinstall MT4 McAfee finds the virus again. If I unistall and redownload/reinstall MT4, the compiler error shows up again as well and can't be used. Is anyone else having this problem?