+ 0 Votes Power management settings for LAN adapter robo_dev 3 years ago Set the general PC power settings to 'always on' and make sure the 'remove power from this device to save power' box is not checked.Check to see if the IP address is changing, as 12 hours sounds like a typical DHCP scope time. Set PC to static address."The system has detected a possible attempt to compromise security" is a sign that either there's a personal firewall set incorrectly or the LAN adapter is losing power, failing, or both. + 0 Votes power settings jrusidoff 3 years ago Thanks- I already had general to 'always on' but just unchecked the box allowing the nic to be turned off to save power. If that doesn't work, I will try the static IP...I had thought of this, but wanted to keep all the workstations dynamic. + 0 Votes If all that fails... robo_dev 3 years ago There are some advanced settings in XP that deal with SMB connections timing out.But your 'security message' error is a specific symptom that the PC is losing LAN connectivity. Specifically, the PC is not properly doing the Windows Kerberos security authentication, which could only happen if the ethernet adapter is shutting down, is faulty, or something like a bad cable or bad ethernet switch port.One thing to try would be to set a cmd prompt window to ping something continuously, and write it to a text file.e.g. ping -t 192.168.0.1 >log.txtThat would keep the LAN connection alive, and also tell you if something is failing at the 12 hour mark. + 0 Votes losing LAN connectivity jrusidoff 3 years ago Thanks for your help...so far nothing has worked for me. It is strange that it never loses connectivity to the Internet, and the server-based antivirus updates every 5 minutes from the exact same server that I am trying to reach to get this person's folder! Crazy...checked switch ports, changed cables, but have not changed the NIC itself yet. Funny that is just seems to be connected with the domain account. There is probably one little box either checked or unchecked that I haven't found somewhere, but for the life of me I can't figure out what is different with this account than with all the others.Thanks for all the help! + 0 Votes I am NexS 3 years ago Having a (possibly) similar issue where computers seem to, after being left on overnight, lose their network connection.The only way the user can get onto the network is to reboot the computer. I've put it down to dying hardware.It's not uncommon for manufacturers to manufacture hardware that will die after the warranty period expires. It makes people buy new hardware -- keeps the dollars rolling in, instead of having their customers happy with their computers for years on end.EDIT:One thing you might try, as a workaround, is to have the 'Boss' turn the computer off every night and set the BIOS to wake it up every morning. That is, if rebooting fixes your problem. + 0 Votes re-booting jrusidoff 3 years ago That activity is over the boss's head, as she is a stone cold idiot! har... + 0 Votes Kerberos is VERY Jasonjb1222 3 years ago Kerberos is VERY sensitive to time differences. Do you have an NTP server? Is it linked to the workstations through a GPO or login script that would reset the time back to normal after a reboot or logout?I would think, after 12 hours or so, if her clock (local) is drifiting back or forward, than this may be your issue. The only thing that would be non funtional would be the network shares and internet would continue to work. The error message is strange however... Using Symantec Endpoint by any chance? + 0 Votes Did you solve this problem? radrick55 2 years ago I am having the same exact problem. Machine works OK during the day then next morning LAN resources are not available, but the Internet is accessible. Antivirus is active and up to date. This started recently. The machine has worked fine for years. Also, it has been kept updated with all the Windows Security Updates.Any solution? + 0 Votes Did you solve this problem? radrick55 2 years ago I am having the same exact problem. Machine works OK during the day then next morning LAN resources are not available, but the Internet is accessible. Antivirus is active and up to date. This started recently. The machine has worked fine for years. Also, it has been kept updated with all the Windows Security Updates.Any solution?