PiT

Yeah, but if you have Self-defense enabled, you can't delete those files. When you disable it, you'll need restart. In many cases you simply cannot restart server...

I have Self-defense enabled and for me worked -> 1) tools / sysinspector -> create snapshot 2) during snapshot creation -> update / update virus signature database 3) setup / enter entire advanced setup tree / miscellaneous / remote administration / interval -> 1min wait until the database updates to 12303 or newer 4) click on update / update virus signature database again -> you'll get "error opening socket" again 5) tools / sysinspector -> create snapshot again 6) during snapshot creation -> update virus signature database again 7) delete both sysinspector snapshots [wait after they are created] 8) setup / enter entire advanced setup tree / miscellaneous / remote administration / interval -> back to time you had before change 9) update virus signature database again -> all is OK For me this fixed all my clients without the need of restart or turning of self-defense. So basically your workaround triggered two times in a row... Without step 4) this workaround didn't work.

From what I can tell a restart of the server does not get it working again. I was only able to get a server to keep downloading updates by uninstalling, reinstalling & NOT rebooting again. Exactly the same here. Uninstall+install or update (e.g. from 2011 to 2015 or 2017) and NOT rebooting again. Repair install doesn't work either.

Same problem here since yesterday :-/ All my Windows Server 2012R2 machines after last restart stopped communicating with ERA. Not only virtual ones (Hyper-V) but also physical hosts. Exactly the same situation as you described. Tried to uninstall last 2 waves of Windows updates on one machine, but it didn't help. Nothing changed in our network before/after the EFS stopped communicating. Tried with EFS 4.5.12011, 12015 and 12017. All stop communicating and throw "Error opening socket." after reboot.

Now, since last windows update, I've the same problem with EFS connected to local ERA 5. ERA 5 // 20 EEA 5 clients - all connected and communicating = OK // 1 EMS client - connected and communicating = OK // 9 EFS clients - one on 32bit W2008R2 - connected and communicating = OK // 8 on 64bit W2012R2 - all 8 throw this same error. I've tried to reinstall them (and also tried luck with uninstalling all applied windows updates on one windows server). After reinstall they work to the next reboot. After reboot they stop to communicate and throw "error opening socket" again.