Cmappstub.exe is a Trojan.Cmapp. Cmappstub.exe downloads and display advertisements. Cmappstub.exe tries to terminate antiviral programs installed on a user computer. Related files: %ProgramFiles%\CMAPP\cmappstub.exe %ProgramFiles%\CMAPP\Client\cmappclient.exe %ProgramFiles%\CMAPP\Client\cmappmf.dll %ProgramFiles%\asys\Stb.exe %ProgramFiles%\asys\VFX8.0-1.exe %Windir%\sysnet.exe %Windir%\snuninst.exe %Windir%\svc.exe %Windir%\visfxun.exe %UserProfile%\Local Settings\Temp\cmappsetup.exe Adds the value: "CMAPP" = ""%ProgramFiles%\CMAPP\Client\cmappclient.exe"" "Sysnet" = "%Windir%\sysnet.exe" to the Windows startup registry keys. More info: http://securityresponse.symantec.com/avc... Removal: Kill cmappstub.exe process and remove cmappstub.exe from Windows startup using antivirus (also check How To Remove section)Startup Optimizer.