I sent you a PM advising where to find your topic.
As a general policy, Bleeping Computer does not offer advice
on how to run ComboFix unless we asked someone to run it or if there is a problem with the computer caused by running the tool. This is because people should not be using ComboFix without being advised to do so by a trained expert (i.e. Malware Response Team) who is assisting a member deal a malware issue on that system. When issues arise due to complex malware infections, possible false detections, problems running ComboFix or with other security tools causing conflicts, experts are usually aware of them and can advise what should or should not be done while providing individual assistance. When false detections are identified, experts have access to the developer and can report them so he can investigate, confirm and make corrections. Those attempting to use ComboFix on their own do not have such information and are at risk when running the tool in an unsupervised environment.
Further, using ComboFix is only one part of the disinfection process. Preliminary scans from other tools like DDS
should be used first because they provide comprehensive logs with specific details about files, folders and registry keys which may have been modified by malware infection. Analysis of those logs allows planning an strategy for effective disinfection and a determination if using ComboFix is necessary. Please read the pinned topic ComboFix usage, Questions, Help? - Look here
If you ran ComboFix just to see what it does or finds, also be aware that ComboFix was never meant to be used
as a general purpose malware scanner like SuperAntispyware or Malwarebytes' Anti-Malware which scan individual drives or different folders on a computer for viruses.
With that said, please describe what specifically when the illegal operation message appears? Is it while running ComboFix itself or when you are doing something else.