Currently me ESET Smart Security 9 sits as usual, being quiet. However as soon as Outlook 2016 is opened things go very wrong! Firstly, Outlook usually hangs on opening the client, waiting for the ESET plugin to begin. Once Outlook is open, ekern.exe shoots up using 100% CPU (100% of a core), and the memory goes out of control. Normally it sits around 150MB, but with outlook I've seen it grow to over 800MB of memory!! The ESET GUI does not show any files being scanned at all. On a plus side, to resolve this I took the following steps: Uninstalled ESET and re-installed Uninstalled Office 2016 and re-installed Clean install of Windows 10 from media (not refresh) None of these solve my issues at all! Does ESET have a problem with POP accounts, especially with very large ones? I have a second Windows 10 machine with outlook 2016 which poses no problems with ESET on it, but that only has two Exchange accounts whilst my main machine (one with the problems) has the same Exchange and a POP account. The POP currently is at ~3GB file. Any help?