What an in-place Windows 2000 upgrade changes and what it does not change

When you do an in-place upgrade of Windows 2000, some existing information and settings are changed, while other information and settings remain the same. This article explains what changes and what remains the same after an in-place upgrade.

Doing an in-place upgrade means installing a new version of a program--for example, Windows 2000--over an existing version of the program.

What an In-Place Upgrade Changes

An in-place upgrade:

• Rolls back any hotfixes, service packs, and Microsoft Internet Explorer upgrades to their base versions.
• Refreshes the registry and restores default registry values.
• Reapplies default permissions.
• Reregisters Component Object Model (COM) components and Windows File Protection (WFP) files.
• Reenumerates Plug and Play devices, including the hardware abstraction layer (HAL).
• Reenumerates and changes drive letters, based on the current drives and partitions that are seen during the in-place upgrade and on the rules that are documented in the following article in the Microsoft Knowledge Base:
  234048  (http://support.microsoft.com/kb/234048/ ) How Windows 2000 assigns, reserves, and stores drive letters

What an In-Place Upgrade Does Not Change

An in-place upgrade:

• Does not change the installed components and programs.
• Does not change any passwords.
• Does not change third-party registry entries.
• Does not change the role of the computer to be a member server. However, be very careful about performing upgrades on a domain controller. When it is possible, perform a system state backup, or have another domain controller seize the roles from the server as a precaution.

Note that if you upgraded your computer from Microsoft Windows NT 4.0 Workstation, the profiles were kept in the Winnt\Profiles folder. When you perform an in-place upgrade, the Setup program creates a Documents and Settings folder and points the registry profile settings to that Documents and Settings folder. You must go into the registry and manually change the path for the profiles back to Winnt\Profiles.

For additional information about user profiles, click the following article number to view the article in the Microsoft Knowledge Base: For additional information about performing an in-place upgrade of Windows 2000, click the following article number to view the article in the Microsoft Knowledge Base: