We are experiencing a strange group policy problem. We have a number of policies, which are applied to different ICT rooms as needed (some are managed software installation, others config etc). In most locations, all GPs work without any problem. However, in two locations, we are getting sporadic application of the policies - mainly the software installation ones. It's happening with two different makes of machine (so not the PC hardware, network cards, etc), and the links between the rooms and the main core of the network are both minimal (at most two hops).
If we bring one of the affected machines in to another location (where this problem isn't apparent), then the GPs apply instantly. We think this may be something to do with the switches - both of these affected locations have new switches; they're the same make as the others (3com), but newer models. Can anyone think of any switch config that might cause this problem?! General network comms aren't affected... weird!!
Are the switches running the latest firmware? We've had a Netgear one that was unstable out of the box and an Allied Telesyn one which would just reboot constantly when connected. Both issues were addressed with the lastest firmware. If you phone a suport line that's the first thing they'll check.
Are you having the problems when students are in the room? If so - it might be that they are pulling the network cables to try and get round the security settings that you are trying to apply. We are having a spate of this at the moment. Anyone got a firm fix for this?