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There are circumstances ComboFix will hang
or stall at various stages
due to malware interference, failure to disable other real-time protection tools or the presence of CD Emulators
(Daemon Tools, Alchohol 120%, Astroburn, AnyDVD) so that it does not complete successfully. Also, depending on how badly a system is infected, ComboFix may take longer to complete its routine than it normally does or fail to run properly. While that is not normal behavior, it is not unusual.
Terminating instances of CF*****.3XE processes in task manager is one solution but there are other related process which in some cases may need to be terminated as well. In our replies to Killer_Wolf we did not provide specific instructions because he was already receiving assistance from a trained Helper who knows this information. When folks are receiving such assistance we do not interfere for the reasons cited in my previous reply.
BTW, anyone reading this topic should also read: ComboFix usage, Questions, Help? - Look here