Windows 7: Network Credentials Getting Lost

I am using Win 7 Pro 64bit on a 2003 SBS. Everything has been working fine for the last three months, but this week, the computer keeps forgetting my network login credentials. I log in to the Win 7 machine user and domain as usual with my network login and password and everything is fine for 2 or 3 hours, then suddenly I dont have access to drives that are mapped to the server drives. I get a dialog box saying that the drive is not accessible.

I can get to my server drives by going through the network icon below my mapped drives in File Manager, but it askes me to reenter my login and password. Then I can get to my server drives, but sometimes the mapped drives will respond to this and sometimes they won't. It seem like half the time I have to remap the drives to get access, the other half of the time I can use them immediatly. This is becomming a real pain in the butt, I am having to do this 2 or 3 times a day.

I should also add that everything is wired on gigabit eithernet.

I should add to the above what may be a related matter, is that for the past few weeks, when I connected to my server drives, the display of the file list has been really slow. It would often take 20 seconds or so to list 30 or 40 files. On my XP machine which is on the desk behind me, the server connection is fine and the files display almost immediatly. The 7 machine, which is a much faster machine than the XP machine, has never been as fast listing directory contents as the XP, but it has always been pretty close. Now it is agonizingly painful to watch that Win 7 green bar creep across the top of the file manager window.

This may relate to your problem.
Windows 7 Professional randomely losing mapped drives

Which eventually links to this fix which has to do with authentication issues.
You may experience authentication issues when you access a network-attached storage device after you upgrade to Windows Server 2008, to Windows Vista, to Windows Server 2003, or to Windows XP

There are similar complaints about this problem all over the internet with no clear resolution.

Thanks, I will try this out. It's funny that it was working without a hitch for about 3 or 4 months, now its several times a day. Recently I added Norton Antivirus 2010 and Comodo firewall. I think that they might have modified some settings that got this started. Hopefully the above procedure will fix it.

With the A/V and firewall nothing is for sure. Most likely that is what caused your problems to begin with. When those programs update automatically it can change the behavior of them to an undesirable state.

I think that I have found the problem. I removed Norton Antivirus 2010 and everything seems to be working really well. My directory file list times are about 5 to 10x faster than before, and I have not had any server connection problems so far. I will post again after about a day to let everyone know if it still seems to be the fix (for me anyway).

I dont know if its Win 7 or just the 64 bit aspect that seems to be so problematic for software developers. I loaded the new 64 bit version of Zone Alarm last month and it killed my machine, and the developer claims that it works fine. Many posts on the internet, and my own experience prove otherwise. I have been using Zone Alarm for about 10 years and love it, but I would expect the major software houses to have their QA/QC in better order than this. It seems that to save money everybody is leaving the debugging up to the paid users.

Oh by the way, I was able to fix the zone alarm problem by booting into safe mode and removing it. It would not boot at all into normal mode.

I can't say I'm surprized at all. Indeed Zone Alarm, Eset, Outpost, Norton, Avast and probably a few more can wreck havoc with any type of Networking in Windows 7.

It may take a awhile longer before those A/V's are worth using again. I can't in good faith use any of them because I see so many problems associated with just about all A/V software's.

At any rate I'm glad you removed Norton which seems to have solved the problem. I shall mark this one as solved.