I'm not sure if this could be caused by this, but after one of mintUpdate's automatic upgrades the booting screen have been changed.
When the mint logo is showing, a notice below it tells me (or rather used to tell - see below) that it is searching for wi-fi connections. Usually I keep wi-fi switched off, and use wired connection (because wi-fi tends to be unstable at my workplace).
But the real problem happened when one day I ran my laptop with the (Ethernet) wire plugged off. I haven't time to read the notice, but it had said something alike "Because I haven't found any network connection I'm switching off all the networking". And indeed it did so: when my desktop finally showed on there was no sign of it. Scared, I rebooted the laptop with the wire plugged on and I got the connection back but...only wi-fi! Also:
- wire connection - the system behaves as if it doesn't exist. In nm-aplet's menu there is "Wired networks: device not managed". No application can connect when no wi-fi network is selected. But when I use ifconfig it tells everything is OK (it is up, have got an IP, and is broadcasting)
- wi-fi - now it is even more unstable than before. Even if nm-aplet's icon shows signal I can use the connection only about 2 minutes - then it just doesn't respond.
- two network managers - maybe it is it. Except 'Network Connections' application (the same accessible via nm-applet menu) there is another simply called 'Network' (runs mate-network-admin. Both of them shows a wired connection. But while in my 'standard' (the first one) manager nothing have been changed (no settings have been altered) in the new one there is something called 'roaming mode' and except wi-fi and wired there is also 'PPP dial-up' (which is VERY strange as my laptop can't do any 'dialing' at all).