I've had this problem on 2 different networks with 2 different configurations (Domain/Workgroup) where the only common software is eset smart security 4.0 both networks were eset nod32 upgraded to smart security with nod32 manual uninstalled Some details of each network Network A. 6x PC (All XP sp3) (All Smart security 4.0) 1x Server SBS2003 (NOD32 AV 4.0) Windows Domain all PC joined to domain PUSH install of Smart security using eset server and remote console Network B. 8x PC (All XP some SP2 some SP3) (All Smart security) 1x Server 2K3 (NOD32 AV 4.0) Windows workgroup all pc in same workgroup Smart Security installed maunally but then pointed back to server to manage. On both networks at exactly 4.01pm each day I get a master browser election triggered where at least 1 pc will challenge to be master browser. I also get a DCOM error on the server at the same time, when this happens all users get disconnected from the server and have to reboot their machines this happens on both networks After resolving the master browser by changing some reg keys, I still get the dcom error. While trying to resolve this I asked each user on the network A to turn off the firewall (right click system tray and disable network filtering) this seemed to work as the network (network A) did not go down. I then asked them to try the same thing the next day and 1 user forgot to do it and they were the only 1 to get disconnected from the network at 4:01pm I've disabled the firewall by pushing out a new configuration to each client and this has stopped the network disconnections. I would like to have the firewall working obviously but I can't have the network going down each day. Any suggestions, or more information needed just say.