It's understandable this happens.... same with other anti-virus companies, etc. however when an update like 5418 (or at least three other past occurances I can recall), it would be nice if ESET was "self-healing". I propose an "Emergency Mode" for ERA, where it instructs clients on their next update cycle to disgard their virus definitions (since they've probably got the bad one), and instead to download and install the last known good definitions. Perhaps an option of 1 - 3 previous defs to store backups of and push these out in the event the latest update is... shall we politely say "flawed" seriously. Then some logic to NOT include the duff update in the backups, and to try the latest update when a new one is released after an emergency situtation has been enabled (a big button on the ERA toolbar would be good). This way, an admin can hit one button, and hopefully prevent clients picking up the bad update, and perhaps clients who already have it, can be re-updated to a previous version. Perhaps also, some kind of "staging" option, where clients in a group get the latest update, whereas clients in another group get the "latest - 1" update, or a user enterable option of how many back, although the recommendation would be not to exceed.. say 5. With these options, bad definitions may not be such a problem, or quickly corrected without having to wait for a new definition to be released by ESET.