i was running into a very similar problem with malwarebytes and TrendMicro WFBS 6 where my after virus definition updates, my client's PCs would either freeze upon the behavior monitoring service restart if the computer was logged on when the updated definitions got pushed out from the server, or upon login the next day if it was a laptop for example that was off-site when the update happened. This went on for three months...i have numerous users who access their PCs remotely so having freezes happen overnight and on weekends was a very bad thing. I went around and around with Trend Support (including generating crash dumps and sending them to Trend for analysis) and got some great help here from Jack Lewis in corporate tech support. to make a long story short (as i don't have all of my notes accessible to me)...i finally got somewhere (i am doing this from memory so don't have all the specifics readily available) Trend said their behavior monitoring service is being blocked by MBAMProtector (i believe part of mbamservice.exe)...which is causing problems with the service restarting...hence the workstations freeze. In working with MBAM corporate tech support, we figured out that by disabling the protection module so that it doesn't start with windows...the updates could happen and the PCs wouldn't freeze....a sufficient workaround...I agree that MBAM catches more than trend does...although having on-access scanning enabled for both would be nice...i use MBAM more for scheduled scans anyway... i continued working with trendmicro who sent me a test behavior monitoring debug pattern to see if with it (and the protection module ENABLED) it will work...it did... i have reported my findings back to them...and they said they are going to write a hotfix for this...i don't know if it's specifically for me or they will make it public...but i will keep anyone posted who is interested... I hope this makes sense...i am trying to write it from memory...if anyone has any questions, i'd be happy to answer them. Thanks Jeremy Whiteman