I hate patching...

Well, another planned 6-hour server patching downtime has turned into 18-hours of pain. The automated tools which we use to apply hotfixes and service packs worked like a charm. Because we reboot servers so infrequently, though, reboots are occasionally frought with danger; and this was no exception.

One server (Win2k) failed boot, showing an error during the text-mode progress bar. The error message was "Loader Error 3", which apparently is often associated with a bad boot sector. The recommended process to address was:

1. Backup user data (if possible)
2. Boot to recovery console
3. Run FIXBOOT
4. Reboot

This (theoretically) resolves the problem - unless the system registry hive is too large to load in the first 16MB of RAM at boot time (along with the kernel and HAL and core drivers). That was the case here. I've seen this before, but normally we see a corrupted hive error.

Fortunately, we'd seen this before, so we had a base system hive (default from base build with local customizations imported from the 'big' hive) in %windir%\system32\config. Rename the old hive file, rename the new base hive file to system, and reboot. We're good to go.

The other systems are three Win2k3 servers with Citrix MetaFrame XP which all blue-screened with 0xC000021A stop codes on boot after installing SP1. This stop code