I am not sure of this is related to the known and supposedly fixed issue regarding USB drives. I do use several external USB drives but I'm not seeing a direct connection to this lock-up. This is my system: Windows 7 Ultimate - Service Pack 1 8 GB RAM Intel i5-2400 ASUS P8Z68-V, latest stable BIOS 3 SATA drives internal 1 USB-HDD 1-2 USB flash drives 4 mounted network drives I'm using absolutely no "known conflicting software" from this forum's sticky, nor has any of it ever been installed on this system. Malwarebytes used to be installed, but has been removed thoroughly (uninstall plus official cleaner), there is no trace of the MBAM service left. If realtime protection is enabled in NOD32 v188.8.131.52, I'm experiencing odd and seemingly random freezes. My system can run rock solid and stable for a whole week, only to freeze with this error five times in one day. The symptoms are always the same. ekrn.exe suddenly uses 100% of one core and halts all I/O access to everything but network drives (which are excluded from scan). Subsequently, every program trying to access a drive freezes one by one. Occasionally the system recovers from a freeze, sometimes after 30 seconds, the longest I waited and actually saw my system recover from this lock-up was 15 minutes. But more often than not the only way out is to do a power-cycle. If realtime protection is disabled, but everything else is in its default state (HIPS is enabled) I'm still seeing similar and occasional CPU spikes by ekrn.exe, but there is no freeze or lock-up. The system is running 100% stable if realtime protection is disabled. I have no idea how to solve this, but if I can't, I'll have to find a different AV solution.