Windows Longhorn build 4000
| Build of Windows Longhorn | |
 | |
| Architecture | x86 |
|---|---|
| Compiled | 2002 |
Windows Longhorn build 4000 is an unleaked build of Windows Longhorn that was mentioned in the setup of Longhorn builds up to and including build 4033, where it states that a user cannot perform an upgrade installation on a build lower than 4000.