All users report ACAD2009 regularly locking up.

[Anonymous]

Something very odd has started to happen with all our CAD workstations. All CAD users report ACAD2009 regularly locking up. Locks up for a few seconds for all users simultaneously every minute or so. Started about a week ago. Happens fairly often at certain times of the day, but at other times it doesn't happen at all.
We have regular MS and AV updates on all our PCs, but non-CAD users don't report a problem, so I don't think this is the cause.
All CAD users have ACAD2008 and 2009 installed, and CADworx2009. Some users are running CADworx with ACAD2009, but others are just using standard ACAD2009 in 2D. All installations get their ACAD licences from a Flex server. We have plenty of spare licences available on this server. CADworx licences are from local dongles.
ACAD's automatic updates have been disabled for 2 users, but this has made no difference (update interval was set for something like 4 hours anyway).
When ACAD locks up, there are no clues in Task Manager: processor load is low, no processes hogging processor or RAM. No unusual processes running. No problems with other apps (and no problems getting to Task Manager itself), only ACAD seems to be affected. So I don't suspect a virus or malware.
Suspect that maybe some recent MS or ACAD update has gone on which ACAD doesn't like. I would guess that ACAD is trying to contact an Internet site at regular intervals. Don't think it's the licence service, as that usually just checks when ACAD is started up.
I will try wiping and re-installing ACAD on one of the machines, but does anyone have any ideas?
Has anyone else experienced this problem?

[arcticad]

Sounds like it's an issue with your network. if the CPU on your server is maxing out.
Yeah I'm talking to you Symantec Antivirus. it can cause everything on the network to freeze.
Autocad is constantly checking files on the server.

[edwa8511]

We have similar problems. Why does the software keep looking to the network/server? If everything is installed at the computer, not over the network or through a server, can this be avoided?

Please let us know what you have found or if you have any ideas. This is going from annoying to wasteful...

[arcticad]

This is my setup

I have a File Server (Linux Based) that is separate from the
Domain Controller (Windows Server).
The File server is on the Active Directory.
If I connect directly to the File Server the system is slow.
If I connect to the DFS on the domain it works much better.

This is what I did to help my issues.

1. I placed any template / font(shx) into a local folder. Set Search path to Match
2. Set my DNS to the Server IP First and then to the Router IP Next.
3. Set the WINS to the Server IP.

If you have any Xref's on the file server AutoCAD is constantly checking the files to see if they have changed.