I had to create a restore point manually a bit earlier, and noticed immediately that there was no hard disk activity at all, a few seconds later all running apps started to freeze one after the other, skype, then Chrome and finally Windows. There were two moments where I could create an avastsvc dump file (will upload it) and hit ctr-alt-del to reboot without forcing a shut down. Sorry guys, must uninstall the behavior shield again.
edit: probably unrelated, while starting the reboot, I was prompted to allow a "jaucheck.exe" connection, thought that was some java stuff and allowed it... can't find the executable on my disk now, and no rule about it in AIS firewall UI... may be it's just in rules.xml, I'll have a look... edit: no, nothing