I recommend you read through this laundry list of Windows 2000 Service Pack 4 (SP4) experiences that readers have sent me. I've edited the comments for clarity and readability. Based on these comments, apparently SP4 introduces a problem with Windows 2000 Server Terminal Services, and a documented problem exists with the Multiple Universal Naming Convention Provider (MUP) component, mup.sys. Some people are also seeing incredibly long delays during system restart and logon, but we haven't determined the source of the delays. If any of you want to contact the author of one of these comments, send me a note and I’ll forward it to the originator. And please, keep sending your feedback my way.
• We've upgraded two terminal servers to SP4, and they both run Captaris’s RightFax client. We're running RightFax 8.5, the latest version, and have about 40 users. We haven't upgraded our RightFax server, but so far our client systems haven't had any problems.
• I tried to upgrade my Dell PowerEdge 2650 server to SP4, and it always gives me the error message Unable to write ScriptMaps metabase entry. Pressing Enter produces the message Failed to execute regsvr32.exe. Error Code is 5. I stopped IIS Admin, FTP, and the WWW service before the upgrade. I also deleted the .htr, .ida, .idr, printer, and some other extensions in the IIS Config.
• After I installed SP4, during boot-up the monitor displays the message applying security policy (or something similar) and would take 20 to 30 minutes to boot. I rebooted several times, and the message and delay kept recurring. The closest reference to this that I could find on the Microsoft Web site was the article "Security Group Policy Is Applied During Every Startup Process" (http://support.microsoft.com/?kbid=329178), which states that SP4 resolves this issue. After uninstalling SP4, the problem has gone away. My system, a Win2K Professional SP3 system, is a member of a workgroup.
• As reported in the Novell forums, mup.sys in SP4 produces a blue screen or reboot if you have the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Mup\DisableDFS registry subkey set to 1. As a workaround, you can set DisableDFS to 0. The problem occurs regardless of the networking software used. To reproduce the problem, you can do the following:
- Install SP4 on a Win2K system and set HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Mup\DisableDFS to 1 (of type REG_DWORD).
- Reboot for the setting to take affect.
- Map a drive to that computer from another PC.
- Disconnect that mapped drive from either the remote or host computer; the host PC will immediately produce a blue screen.

In some cases, I had to map the drive several times before the blue screen occurred. Novell reports that Microsoft is aware of the issue and is developing a hotfix.
• We're using Win2K workstations in a network with a Microsoft Small Business Server (SBS) 4.5 server and a Win2K server. After we installed SP4 on some workstations, they all started to produce a blue screen, with the message Stop 0x00000001e (0xc00000005,0xbfeaed16, 0x00000000, 0x00000000) KMODE_EXCEPTION_NOT_HANDLED Address: bfeaed16 base at bfeae000, datestamp 3e25bc59 - mup.sys.
• The Microsoft article "List of Networking Fixes in Windows 2000 Service Pack 4" (http://support.microsoft.com/?kbid=815023) explains that SP4 replaces mup.sys to solve a buffer overflow security vulnerability. I've seen articles in several newsgroups linking this problem with the Novell client. In the past, we've used a Novell server, and therefore a Novell client was installed on these systems. We uninstalled the Novell client and shut down the Novell server. Today, I found the following post in the newsgroups:

”There's a problem with the mup.sys in SP4. As a temporary workaround, set HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Mup\DisableDFS to 0. This gets rid of the blue screen." Microsoft is supposedly working on a fix (updated MUP) according to another poster. I haven't been able to test these solutions because we uninstalled all SP4 installations.

• I installed SP4 on a Dell PowerEdge 4400 server running Terminal Services and several other commercial applications. After the upgrade, Windows Update no longer works. The update client stops working when the message Windows Update is looking for available updates 0% complete appears. I also had problems with users logging on to a terminal server. The (Admin Tools) "Terminal Services Manager" program failed to connect to the server after several hours of running (just getting "?"). A reboot temporarily fixed the problem, but it reoccurred after several hours of uptime. In desperation, I reapplied SP4, which seems to have solved the problem. I'm not installing SP4 on any other servers until I hear better news from others!
• I installed SP4 on three domain controllers (DC), a terminal server (member server), and about 25 workstations so far (thank God I stopped there!). After the installation, the terminal server started locking up user sessions and I need to manually delete the sessions before Terminal Services clients can reconnect. I've also noticed slower logon times, and two legacy workstations that have only 64MB of memory had to be rebuilt because they were constantly producing a blue screen after the upgrade.
• Users have experienced strange instances in which Microsoft Outlook or any other legacy Microsoft Office application (we're forced to use Office 97 because of some home-built applications) won't start, producing the error message The Program is not registered properly. Please run Setup again. Can't find this file. Make sure the path and file name are correct. Redeploying the software only worked if I altered local permissions for the user, logged on with each user's credentials, and reinstalled Office. A bit lengthy for a 1000-workstation network!
• I'm not yet certain this is the case, but since I upgraded two DCs and added an extra one, the new DC can't obtain SAM data and can't be used to add accounts. The event ID is 16650 with source SAM (an event that doesn't appear to be documented on the Microsoft TechNet site). I'm about to rebuild the new server and see whether I experience the same problems.
• We recently downloaded and started installing SP4 on new machines and upgrading existing systems. We have desktops ranging from a few Pentium 1 Gateways to mostly Pentium 4 Dell PCs. Our basic build on these machines is Win2K, Office 2000, Symantec AntiVirus Client 8.0 running on a manager antivirus server, and Real VNC, among a few others. Our servers run mostly Windows NT, with our antivirus server running Win2K and one DNS server on Linux. We haven't experienced any problems or complaints from any of our users who have SP4 on their PCs (which is about 20 users including my system).
• I made three attempts to upgrade a system to SP4, and all of them failed. During the first attempt, the installation simply hung. The second two attempts finished, but the server didn’t function as it had before the installation. The biggest problem I noticed for the "successful" installations was Internet connectivity. The server itself had issues, such as slow or nonloading pages. In addition, it appeared to affect the proxy server as well, and none of the clients could access the Internet either. Eventually, I had to remove SP4. I should have known better and waited for SP4a. The failed attempt left the machine in a horrible state, and I couldn’t even remove SP4. I had to go back and reapply SP3 to get the server to function as usual again. I wish I had read your article first—it could have saved me 2 days of headaches.
• I have a Garmin eTrex GPS receiver and sometimes hook it up to a laptop running Microsoft AutoRoute to create a crude but portable satellite navigation (SatNav) system. The eTrex serial connection is very simple: 4800bps with no flow control, but it works. After installing SP4, Win2K Pro detected the Global Positioning System (GPS) receiver as a Microsoft serial ballpoint device and started interpreting the position data as mouse movements. In just a few seconds, it had reconfigured my desktop quite comprehensively! Connecting the GPS through a USB to Serial converter produced the same result. The last time we had this problem with NT, it involved NT 4.0 treating an American Power Conversion (APC) UPS serial connection as a serial mouse. The workaround is as follows: Connect the GPS, and after the cursor starts to fly around the screen, disconnect it. The serial ballpoint device drivers are now loaded. Next, go into Device Manager and disable the serial ballpoint device (disable it completely, not in individual hardware profiles). At this point, the GPS receiver can be connected and will work correctly with AutoRoute, and it can be connected directly to the serial port or through a USB to Serial converter. I assume any simple serial device is likely to provoke the same behavior. Apart from this problem, SP4 has been a painless experience.
• SP4 creates major problems for graphics device interface (GDI) printers. I have a QMS Minolta PagePro 1100L at home, and since upgrading to SP4, both of my Win2K machines crash with a Stop 1E in pwgdi.dll (which is admittedly a QMS file, not Microsoft's) whenever the printer driver is accessed: when trying to print, looking at the printer properties, doing a print preview, or in some cases (e.g., Microsoft Word 2002) just launching an application with your default system printer set to a GDI device. Thus far, I've found no mention of this problem in any of Microsoft's support venues (e.g., news.microsoft.com, Knowledge Base). QMS support says that it's aware of the problem and that supposedly all GDI printers are affected (i.e., from any manufacturer, with any driver version). Unfortunately, my printer is an earlier, now discontinued model, and QMS says it won't be updating these drivers any more.
• After downloading SP4 on my Dell 8100 Dimension Win2K Pro computer, the machine reboots continuously and a blue screen message appears and disappears too quickly for me to read.