Several factors can complicate or prevent successful installation of Windows 2000 Service Pack 3 (SP3). Problems can occur when you attempt to upgrade a system with a Distributed COM (DCOM) impersonation level other than the default setting of Identify, a print server that hosts many UNIDRV-based Printer CL (PCL) printers, or a system running a Microsoft Internet Explorer (IE) version earlier than IE 5.5 SP2. Also, you need a Post-SP3 bug fix to correctly display active DHCP reservations in the DHCP snap-in.

DCOM Impersonation Level Prevents Successful Upgrade
A known problem with Windows Installer (%systemroot%\installer\msiw2ksp3\msiexec.exe) causes SP3 setup to fail. According to Microsoft, the Windows Installer packaged with SP3 doesn't install or run on a system when the DCOM default impersonation level is set to Anonymous. Even worse, after the upgrade fails and you reboot, the system retains one SP3 installer file (msisip.dll) that prevents a successful upgrade. If an upgrade fails with the error message An error in updating your system has occurred, and then displays the message Windows is not upgraded to SP3, you might have this problem. When you encounter this bug, any subsequent attempts to install software through Windows Installer and .msi packages, (e.g., another attempt to install SP3, an attempt to install a Microsoft Office update) will produce the message The Windows Installer Service could not be accessed. This can occur if you are running Windows in safe mode, or if the Windows Installer is not correctly installed. To apply SP3 successfully, you need to change the DCOM impersonation level to Identify (the default) and delete the offending msisip.dll.

To change the DCOM impersonation level, open a command prompt and type

dcomcnfg

If some objects aren't registered, the utility prompts you to register them, then displays the Distributed COM Configuration Properties dialog box, which Figure A shows. Click the Default Properties tab, change the setting in the Default Impersonation Level text box to Identify, then click OK.

Next, locate and delete msisip.dll in the system root (typically \winnt\system32\msisip.dll). Copies of this file also appear in %windir%\installer\w2ksp3\.dll and %windir\dllcache. You then should be able to start and successfully complete Windows Installer–based installations, including SP3. You can download a standalone copy of the SP3 Windows Installer for testing at http://www.microsoft.com/downloads/release.asp?releaseid=32832.

Long Delay Upgrading Print Servers
When you install SP3 on a print server that has many UNIDRV-based PCL printer drivers, the server might need 2 hours or longer to regenerate the binary driver files that increase spooler efficiency. After this one-time task is complete, the spooler will accept and process print job requests and the SP3 upgrade will complete successfully. However, during this time, the spooler can't accept incoming print jobs and will respond with a message stating that the print queue is full when users attempt to print a document.

Problems Hiding Microsoft IE, Outlook Express, and WMP
Microsoft’s first attempt to let customers hide or remove IE 6.0 or IE 5.5, Microsoft Outlook Express, and Windows Media Player (WMP) has a few flaws. Although the official documentation states that you can remove these components from an SP3 system through the Control Panel Add/Remove Programs applet's Set Programs and Default Access option, this option doesn't appear on SP3 systems that run version of IE earlier than IE 5.5 SP2. Furthermore, if you hide or remove any of these applications, then uninstall Win2K SP3, the hidden applications remain permanently hidden. To restore these applications on an earlier version of Win2K, you must unhide or reinstall them before you uninstall Win2K SP3.

DHCP Problems
After an upgrade, you might be unable to display or modify DHCP reservations. According to Microsoft, an SP3 DHCP server does manage client reservations correctly, but a bug in the DHCP snap-in prevents it from displaying reservations when there are more than 100 active reservations in a scope. Several sites solved this problem by replacing the SP3 version of \%systemroot%\system32\dhcpsnap.dll with Win2K SP2's version. If you created an uninstall directory before upgrading to SP3, you can find the earlier version in the %systemroot%\$ntservicepackuninstall$ directory. Stop the DHCP Server service, replace the file, then restart the service. You can also solve this problem by installing the most recent version of dhcpsnap.dll, which has a file release date of September 11, 2002. This fix is available from Microsoft Product Support Services (PSS) and is documented in the Microsoft article "The Windows 2000 SP3 DHCP Tool May Show an Empty Reservations List" (Q328636, http://support.microsoft.com) You need to replace dhcpsnap.dll on all systems on which you run the MMC DHCP snap-in to display client reservation information. If DHCP doesn’t display reservations after you replace dhcpsnap.dll, you might need to reboot the system.